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Primary Maths · Year 5Chapter 1 · Place value to 1,000,000
Year 5 · Chapter 1

Year 5 Place Value to 1,000,000: worked examples and questions with answers

By the end of this chapter you will be able to

  • Read, write and partition numbers up to 1,000,000 and say the value of every digit
  • Order and compare numbers up to 1,000,000 and use the signs < and >
  • Count on and back in 10s, 100s, 1,000s, 10,000s and 100,000s from any number, including missing numbers in a sequence
  • Use negative numbers in real life (temperatures, depths and bank balances) and count through zero
  • Round numbers to the nearest 10, 100, 1,000, 10,000 and 100,000 and use rounding to estimate
  • Read and write Roman numerals up to 1,000 and read years such as MCMXCIX and MMXXVI
  • Solve problems and puzzles that use place value, ordering, rounding and negative numbers

You should already know

  • Place value of numbers up to 10,000
  • Counting in steps of 1,000 and finding 1,000 more or less
  • Rounding to the nearest 10, 100 and 1,000
  • Counting back through zero (temperatures)
  • Roman numerals to 100

Where this leads

  • Adding and subtracting numbers with more than 4 digits (Chapter 2)
  • Multiplying and dividing by 10, 100 and 1,000 (Chapters 4 and 5)
  • Decimals and place value to three decimal places (Chapter 7)
  • Place value to 10,000,000 and calculating across zero in Year 6

National Curriculum for England, Key Stage 2 mathematics, Year 5. Content: Read, write, order and compare numbers to at least 1,000,000 and know the value of each digit, Count forwards or backwards in steps of powers of 10 for any given number up to 1,000,000, Interpret negative numbers in context; count forwards and backwards through zero, Round any number up to 1,000,000 to the nearest 10, 100, 1,000, 10,000 and 100,000, Solve number and practical problems that involve all of the above, Read Roman numerals to 1,000 (M) and recognise years written in Roman numerals.

Printable worksheets. Every lesson in this chapter has a free worksheet and an answer sheet to download and print.

Exercise P  Do you remember?

Non-calculator
1
FWhat is the value of the 2 in 5,247?
2
FWhat is 1000 more than 4,572?
3
FRound 3,467 to the nearest 100.
4
FThe temperature is 4°C. It falls by 7°C. What is the new temperature?
5
FWrite 79 in Roman numerals.
1.1

Reading and writing numbers to 1,000,000

Year 5
Read and write numbers to 1,000,000, Value of each digit

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Reading and writing numbers to 1,000,000Coming soon

In Year 4 you worked with numbers up to 10,000. Now the numbers get much bigger. We will go all the way up to 1,000,000, which is one million! Big numbers are easier to read if the digits are split into groups of three, called periods. We put a comma between the periods. Reading from the right, the first period is Ones (O, T, H), the next is Thousands (Th, TTh, HTh) and the next is Millions (M).

Each column is 10 times bigger than the column on its right. 10 ones make 1 ten, 10 tens make 1 hundred, 10 hundreds make 1 thousand, 10 thousands make 1 ten thousand, and 10 ten thousands make 1 hundred thousand. This chart uses counters to show 306,075. The ten thousands column has no counters, so its digit is a 0, a place holder.

ThousandsOnesHTh100k100k100k3TTh0Th1k1k1k1k1k1k6H0T101010101010107O111115
Place-value counters for 306,075. A counter is worth 1, 10, 100, 1k (1,000), 10k (10,000) or 100k (100,000), depending on its column.

Reading a number in words. Read the digits before the comma as one number and add the word thousand. Then read the last three digits. 306,075 is three hundred and six thousand and seventy-five. We put “and” before the last two digits (the tens and ones). Zeros are not said out loud, but they must be written.

Partitioning. This means splitting a number into the value of each digit: 306,075 = 300,000 + 6,000 + 70 + 5. The value of a digit is the digit times the value of its column. In 306,075, the 3 is worth 300,000 because it is in the hundred thousands column.

MillionsThousandsOnes
MHThTThThHTO
1000000
One million. When every column in 999,999 is full, adding 1 starts a new column: the Millions column.

Key words. A digit is one of 0 to 9. A period is a group of three columns. A place holder is a zero that keeps the other digits in the right columns. To partition a number is to split it into the values of its digits.

Key ideas

  • The columns, from the right: O, T, H | Th, TTh, HTh | M. Each is 10 times the one on its right.
  • Commas split a number into periods of three digits.
  • Value of a digit = the digit times the value of its column. The 4 in 340,000 is worth 40,000.
  • A zero is a place holder: 405,060 is not the same as 45,060.
  • In words, say the thousands period, then “thousand”, then the last three digits. Put “and” before the last two digits.
  • 999,999 + 1 = 1,000,000 (one million).
Worked example 1.1.1
What is the value of the underlined digit in 384,729?

Key words. A digit is one of 0 to 9. The value of a digit is what it is worth. A period is a group of three columns: Ones, Thousands, Millions.

Method. The value of a digit depends on its column. Find the column, then multiply the digit by the value of the column.

  1. Write the number in a place-value table. Each column has a name and a value. The coloured digit is the one we want.
    ThousandsOnes
    HThTThThHTO
    384729
  2. Find which column the digit is in. The digit is 8 and it sits in the ten thousands column.
    1 ten thousand = 10,000
  3. Multiply the digit by the value of the column. There are 8 ten thousands.
    8 × 10,000 = 80,000

Check. Say it in words: 8 ten thousands is eighty thousand. ✓

Watch out. The digit is 8 but its value is 80,000. The same digit is worth different amounts in different columns.

Worked example 1.1.2
Write 408,507 in words.

Key words. A digit is one of 0 to 9. The value of a digit is what it is worth. A period is a group of three columns: Ones, Thousands, Millions.

Method. Say the number in parts, from left to right: the thousands period first, then the hundreds, then the last two digits.

  1. Write the number in a place-value table. The comma splits the digits into the Thousands period and the Ones period.
    ThousandsOnes
    HThTThThHTO
    408507
  2. Read each part and say it in words. Say the thousands period as a number and then add the word thousand.
    Thousands period: 408 → four hundred and eight thousand
    Hundreds: 5 → five hundred
    Last two digits: 7 → seven
  3. Join the parts together. Put “and” before the last two digits (the tens and ones) when there are hundreds or thousands before them.
    four hundred and eight thousand, five hundred and seven

Check. Read it out loud. It sounds like 408,507. ✓

Watch out. Zeros are never said aloud. 400,060 is “four hundred thousand and sixty”: nothing is said for the empty columns, but they still need a 0 when you write the digits.

Worked example 1.1.3
Write 300,040 in words.

Key words. A digit is one of 0 to 9. The value of a digit is what it is worth. A period is a group of three columns: Ones, Thousands, Millions.

Method. Say the number in parts, from left to right: the thousands period first, then the hundreds, then the last two digits.

  1. Write the number in a place-value table. The comma splits the digits into the Thousands period and the Ones period.
    ThousandsOnes
    HThTThThHTO
    300040
  2. Read each part and say it in words. Say the thousands period as a number and then add the word thousand.
    Thousands period: 300 → three hundred thousand
    Last two digits: 40 → forty
  3. Join the parts together. Put “and” before the last two digits (the tens and ones) when there are hundreds or thousands before them.
    three hundred thousand and forty

Check. Read it out loud. It sounds like 300,040. ✓

Watch out. Zeros are never said aloud. 400,060 is “four hundred thousand and sixty”: nothing is said for the empty columns, but they still need a 0 when you write the digits.

Worked example 1.1.4
Write “six hundred and five thousand, two hundred and nine” in digits.

Key words. A digit is one of 0 to 9. The value of a digit is what it is worth. A period is a group of three columns: Ones, Thousands, Millions.

Method. Listen for the words “thousand” and “hundred”. They tell you which period and column each part goes in.

  1. Split the words into parts. Each part belongs to one period or column.
    “six hundred and five thousand” → the Thousands period is 605
    “two hundred” → 2 in the hundreds column
    “nine” → 0 in the tens column and 9 in the ones column
  2. Write the digits in a place-value table. Write a zero in every column that was not mentioned. Each period has three digits (except the first).
    ThousandsOnes
    HThTThThHTO
    605209
  3. Write the number. Put a comma between the periods.
    605,209

Check. Say 605,209 in words: six hundred and five thousand, two hundred and nine. It matches. ✓

Watch out. A zero is a place holder. Without it the digits slip into the wrong columns and the number changes.

Worked example 1.1.5
Partition 530,408. Write it as an addition.

Key words. To partition a number is to split it into parts, one part for each digit.

Method. Partition means splitting a number into the value of each of its digits.

  1. Write the number in a place-value table. This shows how many of each column there are.
    ThousandsOnes
    HThTThThHTO
    530408
  2. Work out the value of each digit. Digit times the value of its column.
    5 hundred thousands = 500,000
    3 ten thousands = 30,000
    0 thousands = nothing to write
    4 hundreds = 400
    0 tens = nothing to write
    8 ones = 8
  3. Leave out the zeros. A zero means the column is empty, so there is nothing to add.
  4. Write the values as an addition. Start with the biggest value.
    530,408 = 500,000 + 30,000 + 400 + 8

Check. Add them up: 500,000 + 30,000 + 400 + 8 = 530,408. ✓

Watch out. Write 300,000 for 3 hundred thousands, not just 3. Each part keeps its full value.

Worked example 1.1.6
What number do these place-value counters show?
ThousandsOnesHTh100k100kTTh10k10k10k10kTh1k1k1k1k1k1k1kHT101010O111111

Key words. A digit is one of 0 to 9. The value of a digit is what it is worth. A period is a group of three columns: Ones, Thousands, Millions.

Method. Count the counters in each column. Each counter is worth the value of its column, so the number of counters is the digit.

  1. Count the counters in each column. No counters in a column means a zero.
    HTh column: 2 counters → 2
    TTh column: 4 counters → 4
    Th column: 7 counters → 7
    H column: 0 counters → 0
    T column: 3 counters → 3
    O column: 6 counters → 6
  2. Put the digits in a place-value table. Keep the columns in the same order.
    ThousandsOnes
    HThTThThHTO
    247036
  3. Read the number. Put a comma between the Thousands period and the Ones period.
    247,036

Check. Say it in words: two hundred and forty-seven thousand and thirty-six. ✓

Watch out. A column with no counters is a zero. Do not leave it out.

Worked example 1.1.7
Write “3 hundred thousands, 5 ten thousands, 2 hundreds and 8 ones” as a number.

Key words. A place holder is a zero that holds an empty column so the other digits stay in the right place.

Method. Put each part into its own column of a place-value table. Write a zero in any column with nothing in it.

  1. Read the parts: 3 hundred thousands, 5 ten thousands, 2 hundreds and 8 ones. Each part tells us which column it goes in and how many.
  2. Put each digit in its column. Start with the biggest column on the left.
    3 hundred thousands → write 3 in the HTh column
    5 ten thousands → write 5 in the TTh column
    0 thousands → write 0 in the Th column (nothing here, so write a zero)
    2 hundreds → write 2 in the H column
    0 tens → write 0 in the T column (nothing here, so write a zero)
    8 ones → write 8 in the O column
  3. Read the digits across the table. Put commas between the periods.
    ThousandsOnes
    HThTThThHTO
    350208

    The number is 350,208.

Check. Say it in words: three hundred and fifty thousand, two hundred and eight. It matches the parts. ✓

Watch out. A zero is a place holder. 405,060 and 45,060 are very different numbers.

Worked example 1.1.8
How many hundreds are there in 36,400?

Method. To find how many hundreds are in a number, read all the digits from the left up to the hundreds column as one number.

  1. Write the number in a place-value table. Find the hundreds column.
    ThousandsOnes
    TThThHTO
    36400
  2. Read the digits up to the H column. Every column on the left is a bigger column. They can all be swapped for hundreds. 1 thousand is 10 hundreds, and so on.
    The digits 364, read as one number, are 364.
  3. Write the answer.
    364 hundreds

Check. 364 × 100 = 36,400. ✓

Watch out. Do not just read the digit in that column. There are 364 hundreds in 36,400, not 4.

Worked example 1.1.9
What is 1 more than 999,999? Write it in digits and in words.

Method. Add 1 to the ones column and carry the 1 all the way along. Then write the answer in digits and words.

  1. Write the number in a place-value table. Every column is a 9.
    ThousandsOnes
    HThTThThHTO
    999999
  2. Add 1 to the ones. 9 + 1 = 10, so write 0 and carry 1. The next column is also 9, so the carry keeps going.
    9 ones + 1 = 10 ones → 1 ten
    9 tens + 1 ten = 10 tens → 1 hundred
    … and so on, all the way to the left
  3. Write the new number. Every column is now 0 and there is a new column on the left, the Millions column.
    MillionsThousandsOnes
    MHThTThThHTO
    1000000

    1,000,000
  4. Say it in words. 1,000,000 is 1 thousand thousands. We call it one million.
    one million

Check. 10 × 100,000 = 1,000,000, so there are 10 hundred thousands in one million. ✓

Watch out. 999,999 has six digits. One more has seven. A new column appears when every column is full.

Watch out

Do not forget the place-holder zeros. “Three hundred and five thousand and forty” is 305,040, not 35,040 and not 350,040. Also remember that the value of a digit is not the digit itself: in 460,000 the 6 is worth 60,000.

Exercise 1A  Reading, writing and partitioning numbers

Non-calculator
1
FWhat number do these place-value counters show?
ThousandsOnesHTh100k100k100k100kTTh10k10k10k10k10k10k10kTh1k1k1kHT1010101010O11
2
FAisha has put counters on a place-value chart. What number do they show?
ThousandsOnesHTh100k100k100k100k100kTThTh1k1k1k1k1k1k1k1kHT101010101010O
3
FWhat is the value of the underlined digit?
(a)638,245
(b)92,816
(c)407,153
(d)520,894
4
FWrite each number in words.
(a)38,205
(b)270,040
(c)604,300
(d)900,009
5
FWrite each number in digits.
(a)fifty-two thousand, six hundred and eight
(b)three hundred and forty thousand and seven
(c)six hundred and six thousand, six hundred and six
(d)nine hundred thousand and ninety
6
FPartition each number. Write it as an addition.
(a)482,615
(b)703,040
(c)250,008
(d)96,070
7
FWrite each as a number. Remember that an empty column needs a zero.
(a)6 hundred thousands, 4 thousands and 9 tens
(b)3 hundred thousands, 7 ten thousands and 2 hundreds
(c)800,000 + 5,000 + 40 + 3
(d)200,000 + 90,000 + 6
8
FWhich number has a 7 in the ten thousands column?   A  710,458    B  107,458    C  170,458    D  100,745
9
FHow many are there?   Use what you know about place value.
(a)How many thousands in 72,000?
(b)How many hundreds in 45,300?
(c)How many tens in 8,740?
(d)How many hundreds in 100,000?
10
PSA charity counts coins. It has 4 boxes with 100,000 coins in each, 2 boxes with 10,000 coins in each, 6 boxes with 1,000 coins in each and 5 loose coins. How many coins is that altogether?
11
PSAnswer these questions about six-digit numbers.
(a)What is the smallest six-digit number?
(b)What is the largest six-digit number?
(c)What is 1 more than the largest six-digit number? Write it in words.
12
RNoah writes “three hundred and five thousand and forty” as 350,040. Spot his mistake and write the correct number.
13
RWhich one is different?   400,050    400,000 + 50    4 hundred thousands and 5 tens    450,000
14
RIs this always, sometimes or never true?
“The value of a digit is bigger than the digit itself.”
15
RAmira says, “There are 10 hundred thousands in one million.” Is she right? Prove it.
16
RI am a six-digit number.
My hundred thousands digit is twice my ten thousands digit.
My thousands digit is 0.
My hundreds digit is the same as my ten thousands digit.
My tens digit is 5 more than my ones digit.
My digits add up to 21.
My ones digit is not 0 and I am more than 500,000.
What number am I?
1.2

Comparing and ordering numbers to 1,000,000

Year 5
Order and compare numbers to 1,000,000, Estimate numbers on a number line

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Comparing and ordering numbers to 1,000,000Coming soon

Comparing. To decide which number is bigger, first look at how many digits each number has. A number with more digits is bigger (as long as it does not start with 0). If both have the same number of digits, line the digits up in a place-value table and compare from the left. The first column that is different decides.

ThousandsOnes
HThTThThHTO
482,619482619
482,691482691
The first four columns match (4, 8, 2, 6). The tens column is different: 1 is less than 9. So 482,619 < 482,691.

We use three signs: < means “is less than”, > means “is greater than” and = means “is equal to”. The open end of the sign faces the bigger number. To order numbers, compare them in pairs. Ascending order is smallest first. Descending order is biggest first.

Number lines. To read a number line, work out what one gap is worth: take the difference between two labelled numbers and divide by the number of gaps. This line goes from 0 to 1,000,000 in 10 gaps, so each gap is 1,000,000 ÷ 10 = 100,000. The arrow is between 600,000 and 700,000. If the arrow is not exactly on a mark we estimate a number close to it. Halfway between 600,000 and 700,000 is 650,000.

0500,0001,000,000?
Each gap is worth 100,000. The arrow is between 600,000 and 700,000, so a good estimate is 650,000.

Making numbers with digit cards. To make the largest number, put the biggest digit in the biggest column, then the next biggest, and so on. To make the smallest number, put the smallest digit first, but never put 0 in the first column. A six-digit number cannot start with 0.

Key words. Ascending means getting bigger. Descending means getting smaller. To estimate is to give a sensible answer that is close to the exact one.

Key ideas

  • More digits means a bigger number (if no number starts with 0).
  • Same number of digits: compare from the left. The first column that is different decides.
  • < less than, > greater than, = equal to. The open end faces the bigger number.
  • On a number line, work out what one gap is worth before you read the arrow.
  • Largest number: biggest digit first. Smallest number: smallest digit first, but not 0.
  • Halfway between two numbers: add them and halve the total.
Worked example 1.2.1
Write < or > in the box:   356,742  [ ? ]  356,724

Key words. < means “less than” and > means “greater than”. The wide end of the sign faces the bigger number.

Method. Compare the digits from the left, one column at a time. The first column that is different tells you which number is bigger.

  1. Write both numbers in a place-value table. Lining up the columns lets us compare digit by digit.
    ThousandsOnes
    HThTThThHTO
    356,742356742
    356,724356724
  2. Compare the digits from the left. The first column where they are different decides which number is bigger.
    hundred thousands: 3 and 3 are the same, so look at the next column.
    ten thousands: 5 and 5 are the same, so look at the next column.
    thousands: 6 and 6 are the same, so look at the next column.
    hundreds: 7 and 7 are the same, so look at the next column.
    tens: 4 and 2 are different. 4 > 2, so 356,742 is bigger.
  3. Write the correct symbol. < means “is less than”, > means “is greater than”, = means “is equal to”.
    356,742 > 356,724

Check. Picture a number line: 356,724 is to the left of 356,742. ✓

Watch out. Start at the LEFT (the biggest column). Do not start with the ones.

Worked example 1.2.2
Write < or > in the box:   98,765  [ ? ]  100,234

Key words. < means “less than” and > means “greater than”. The wide end of the sign faces the bigger number.

Method. Compare the digits from the left, one column at a time. The first column that is different tells you which number is bigger.

  1. Write both numbers in a place-value table. Lining up the columns lets us compare digit by digit.
    ThousandsOnes
    HThTThThHTO
    98,76598765
    100,234100234
  2. Count the digits. A number with more digits is bigger (when no number starts with 0).
    100,234 has 6 digits and 98,765 has 5 digits, so 100,234 is bigger.
  3. Write the correct symbol. < means “is less than”, > means “is greater than”, = means “is equal to”.
    98,765 < 100,234

Check. Picture a number line: 98,765 is to the left of 100,234. ✓

Watch out. Start at the LEFT (the biggest column). Do not start with the ones.

Worked example 1.2.3
Write <, > or = in the box:   300,000 + 4,000  [ ? ]  340,000

Key words. < means “less than” and > means “greater than”. The wide end of the sign faces the bigger number.

Method. Compare the digits from the left, one column at a time. The first column that is different tells you which number is bigger.

  1. Write each side as one number. We can only compare numbers when they are written the usual way.
    300,000 + 4,000 = 304,000
    340,000 = 340,000
  2. Write both numbers in a place-value table. Lining up the columns lets us compare digit by digit.
    ThousandsOnes
    HThTThThHTO
    304,000304000
    340,000340000
  3. Compare the digits from the left. The first column where they are different decides which number is bigger.
    hundred thousands: 3 and 3 are the same, so look at the next column.
    ten thousands: 0 and 4 are different. 0 < 4, so 304,000 is smaller.
  4. Write the correct symbol. < means “is less than”, > means “is greater than”, = means “is equal to”.
    304,000 < 340,000

Check. Picture a number line: 304,000 is to the left of 340,000. ✓

Watch out. Start at the LEFT (the biggest column). Do not start with the ones.

Worked example 1.2.4
Write these numbers in order, smallest first:   345,678,  345,768,  354,678,  345,687,  34,568

Key words. Ascending order means smallest first. Descending order means biggest first.

Method. Put the numbers in a place-value table, then compare columns from the left. Smallest first.

  1. Write all the numbers in a place-value table. This lines up the digits so we can compare them.
    ThousandsOnes
    HThTThThHTO
    345,678345678
    345,768345768
    354,678354678
    345,687345687
    34,56834568
  2. Compare the numbers in pairs, from the left. Where the digits in a column match, move on to the next column.
    34,568 and 345,678: 345,678 has 6 digits and 34,568 has 5 digits, so 345,678 is bigger.
    345,678 and 345,687: tens: 7 and 8 are different. 7 < 8, so 345,678 is smaller.
    345,687 and 345,768: hundreds: 6 and 7 are different. 6 < 7, so 345,687 is smaller.
    345,768 and 354,678: ten thousands: 4 and 5 are different. 4 < 5, so 345,768 is smaller.
  3. Write them smallest first. Check you have used every number once.
    34,568, 345,678, 345,687, 345,768, 354,678

Check. Count the numbers: 5 in the question and 5 in the answer. ✓

Watch out. Tick each number off as you write it, so you do not miss one.

Worked example 1.2.5
Write these numbers in order, biggest first:   807,060,  870,600,  806,070,  87,060

Key words. Ascending order means smallest first. Descending order means biggest first.

Method. Put the numbers in a place-value table, then compare columns from the left. Biggest first.

  1. Write all the numbers in a place-value table. This lines up the digits so we can compare them.
    ThousandsOnes
    HThTThThHTO
    807,060807060
    870,600870600
    806,070806070
    87,06087060
  2. Compare the numbers in pairs, from the left. Where the digits in a column match, move on to the next column.
    87,060 and 806,070: 806,070 has 6 digits and 87,060 has 5 digits, so 806,070 is bigger.
    806,070 and 807,060: thousands: 6 and 7 are different. 6 < 7, so 806,070 is smaller.
    807,060 and 870,600: ten thousands: 0 and 7 are different. 0 < 7, so 807,060 is smaller.
  3. Write them biggest first. Check you have used every number once.
    870,600, 807,060, 806,070, 87,060

Check. Count the numbers: 4 in the question and 4 in the answer. ✓

Watch out. Tick each number off as you write it, so you do not miss one.

Worked example 1.2.6
What number is the arrow pointing to?
300,000350,000400,000?

Method. Find out what each small mark is worth, then count on from a number you can read.

  1. Count the gaps between two labelled numbers. The line goes from 300,000 to 400,000 in 10 equal gaps.
    400,000 − 300,000 = 100,000
  2. Work out what one gap is worth. Share the distance equally between the gaps.
    100,000 ÷ 10 = 10,000
  3. Count on from the start to the arrow. The arrow is 6 gaps after 300,000.
    300,000 + 6 × 10,000 = 300,000 + 60,000 = 360,000

Check. Count back from 400,000: 4 gaps back is 400,000 − 40,000 = 360,000. ✓

Watch out. Do not read the nearest label. Count the small marks to find the exact number.

Worked example 1.2.7
The arrow is pointing to a number. Which is the best estimate?   A  150,000   B  450,000   C  650,000   D  950,000
0500,0001,000,000?

Method. Work out what each gap is worth. Then decide which two gaps the arrow is between and how far along it is.

  1. Work out what one gap is worth. The line goes from 0 to 1,000,000 in 10 equal gaps.
    1,000,000 ÷ 10 = 100,000
  2. Find the two numbers either side of the arrow. The arrow is after 6 gaps, but before 7 gaps.
    600,000 < arrow < 700,000
  3. Decide how far along the arrow is. Halfway between 600,000 and 700,000 is 650,000.
    The arrow is close to 650,000.
  4. Choose the best estimate. Pick the option nearest to the arrow.
    C (650,000)

Check. The other options are far away: 150,000, 450,000, 950,000. ✓

Watch out. An estimate is a sensible guess. You do not need the exact number.

Worked example 1.2.8
Use all six digit cards each time to make a six-digit number. Make the largest number and the smallest number.
407295

Method. Make the largest by putting the cards in order, biggest first. Make the smallest by putting them in order, smallest first (with a non-zero digit in front).

  1. Largest: put the digits in order, biggest first. The biggest digit in the biggest column gives the biggest number.
    9, 7, 5, 4, 2, 0 → 975,420
  2. Smallest: put the digits in order, smallest first. That would start with 0, but a six-digit number cannot start with 0.
    0, 2, 4, 5, 7, 9
  3. Swap the first two digits. The smallest digit that is not 0 goes first, then the 0.
    2, 0, 4, 5, 7, 9 → 204,579

Check. Check the smallest has six digits and uses all the cards once. 204,579 does. ✓

Watch out. A leading zero is not allowed: 024,579 is really a five-digit number.

Worked example 1.2.9
What number is halfway between 340,000 and 360,000?

Method. The number halfway between two numbers is the same distance from both. Find the gap between them, halve it, then add that to the smaller number.

  1. Find the gap between the two numbers. Subtract the smaller from the bigger.
    360,000 − 340,000 = 20,000
  2. Halve the gap. Halfway is half of the gap away from each number.
    20,000 ÷ 2 = 10,000
  3. Add half the gap to the smaller number. This moves us to the middle.
    340,000 + 10,000 = 350,000

Check. Another way: add the numbers and halve. 340,000 + 360,000 = 700,000 and 700,000 ÷ 2 = 350,000. ✓

Watch out. Halfway is not the average of the digits. Use the whole numbers.

Watch out

Start on the left when you compare, not the right. 98,765 is smaller than 100,234 even though 9 is bigger than 1, because 98,765 has only five digits and 100,234 has six. And a zero cannot go first: the smallest six-digit number is 100,000, not 000,000.

Exercise 1B  Comparing and ordering

Non-calculator
1
FWrite <, > or = in each box.
(a)356,742  [ ? ]  356,724
(b)89,999  [ ? ]  100,001
(c)400,000 + 5,000  [ ? ]  450,000
(d)620,300  [ ? ]  62,030
(e)seven hundred thousand  [ ? ]  700,000
(f)999,999  [ ? ]  1,000,000
2
FWrite each set of numbers in order, smallest first.
(a)534,210,  534,120,  543,210,  53,421
(b)706,040,  760,040,  706,400,  76,040
(c)999,001,  990,901,  909,901,  999,010
3
FWrite each set of numbers in order, biggest first.
(a)250,639,  205,639,  250,369,  25,639,  205,936
(b)418,000,  481,000,  4,180,  408,100
4
FWhat number is the arrow pointing to?
400,000450,000500,000?
5
FPriya draws an arrow on this number line. What number is it pointing to?
50,00055,00060,000?
6
FThe arrow points to a number on the line. Which is the best estimate?   A  20,000   B  250,000   C  520,000   D  720,000
0500,0001,000,000?
7
PSWhich digits could go in the box to make this true?
4?5,200  >  435,200
8
FFind the number that is exactly halfway between each pair of numbers.
(a)250,000 and 350,000
(b)125,000 and 175,000
(c)680,000 and 720,000
(d)1,000 and 99,000
9
FAmira has six digit cards. Use all six cards each time to make a six-digit number.
309572
(a)The largest number
(b)The smallest number
(c)The smallest even number
10
PSUse all six cards each time to make a six-digit number.
804162
(a)The largest number that is less than 500,000
(b)The smallest number that is more than 500,000
11
PSThe table shows the number of people who live in five towns.
TownPeople
Ashby185,420
Bexley158,240
Corton185,240
Dunmore98,765
Elford205,010
(a)Which town has the most people?
(b)Which town has the fewest people?
(c)Write the towns in order, from the most people to the fewest.
12
PSFour stadiums have these numbers of seats.
StadiumSeats
Arena A62,400
Arena B59,250
Arena C74,500
Arena D60,000
Which stadium has the second most seats?
13
RMei says, “98,765 is greater than 100,234 because 9 is greater than 1.” Is she right? Explain.
14
RIs this always, sometimes or never true?
“If you swap two digits in a number, the new number is smaller.”
15
RAmira says, “600,000 is 10 times as big as 60,000.” Noah says, “600,000 is 100 times as big as 6,000.” Who is right? Prove it.
16
RUse each of the digit cards 1, 2, 3, 4, 5 and 6 once to make a six-digit number that is as close as possible to 500,000. What number can you make? Show how you know.
1.3

Counting in steps of 10, 100, 1,000, 10,000 and 100,000

Year 5
Count forwards or backwards in powers of 10, Find 10, 100, 1,000, 10,000 or 100,000 more or less

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Counting in steps of 10, 100, 1,000, 10,000 and 100,000Coming soon

The numbers 10, 100, 1,000, 10,000 and 100,000 are called powers of 10. Each one is 10 times bigger than the one before. When you count on or back in a power of 10, only one digit changes: the digit in the column with the same value as the step.

Count on in 10,000s from 253,400. Look at the table. The ten thousands digit goes up by 1 each time: 2, 3, 4, 5. The other digits stay the same.

ThousandsOnes
HThTThThHTO
253,400253400
263,400263400
273,400273400
283,400283400
Counting on in 10,000s from 253,400. Only the ten thousands column changes.

Look out for 9s and 0s. When a digit is 9 and you add 1, it becomes 0 and you carry 1 to the next column. So 10,000 more than 395,000 is 405,000. When a digit is 0 and you take 1 away, you swap 1 from the next column for 10. So 1,000 less than 300,000 is 299,000. The swap can go along more than one column.

150,000250,000350,000450,000550,000650,000+100,000+100,000+100,000+100,000+100,000
Counting on in 100,000s from 150,000: 250,000, 350,000, 450,000, 550,000, 650,000.

Missing numbers. To fill the gaps in a sequence, find two numbers you can see. Count the jumps between them, then divide the difference by the number of jumps. That tells you the size of each jump. To find how many jumps there are between two numbers, divide the difference by the size of one jump.

Key words. A sequence is a list of numbers that follows a rule. A power of 10 is 10, 100, 1,000, 10,000, 100,000 and so on. A term is one number in the sequence.

Key ideas

  • Counting in a power of 10 changes only one digit: the one in the column with that value.
  • A 9 going up carries 1 to the next column. A 0 going down swaps 1 from the next column.
  • For 10 more or less, change the tens digit. For 100, the hundreds digit. For 1,000, 10,000 or 100,000, the thousands, ten thousands or hundred thousands digit.
  • To find the step in a sequence: difference ÷ number of jumps.
  • To find the number of jumps: total distance ÷ size of one jump.
Worked example 1.3.1
Count on in 100s from 3,450. Write the next four numbers.

Key words. Counting in steps of 100 means adding 100 again and again. 10, 100, 1,000, 10,000 and 100,000 are powers of 10.

Method. Counting on in 100s means adding 100 each time. Only the hundreds digit changes (unless we carry or swap).

  1. Find the size of each jump. We are counting on in steps of 100, which is 1 hundred.
    Each jump is +100.
  2. Work out the numbers one jump at a time. Always start from the number you have just found.
    3,450 + 100 = 3,550  (the hundreds digit goes 4 → 5)
    3,550 + 100 = 3,650  (the hundreds digit goes 5 → 6)
    3,650 + 100 = 3,750  (the hundreds digit goes 6 → 7)
    3,750 + 100 = 3,850  (the hundreds digit goes 7 → 8)
  3. Write the numbers in order.
    3,550, 3,650, 3,750, 3,850

Check. Go the other way from the last number: 3,850 − 100 = 3,750. ✓

Watch out. Only the hundreds digit changes, unless it is a 9 going up (carry) or a 0 going down (swap). Check the digit before every jump.

Worked example 1.3.2
Count back in 1,000s from 62,500. Write the next five numbers.

Key words. Counting in steps of 1,000 means taking away 1,000 again and again. 10, 100, 1,000, 10,000 and 100,000 are powers of 10.

Method. Counting back in 1,000s means taking away 1,000 each time. Only the thousands digit changes (unless we carry or swap).

  1. Find the size of each jump. We are counting back in steps of 1,000, which is 1 thousand.
    Each jump is −1,000.
  2. Work out the numbers one jump at a time. Always start from the number you have just found.
    62,500 − 1,000 = 61,500  (the thousands digit goes 2 → 1)
    61,500 − 1,000 = 60,500  (the thousands digit goes 1 → 0)
    60,500 − 1,000 = 59,500  (0 thousands: swap 1 from the next column for 10 thousands, then take 1 thousand away)
    59,500 − 1,000 = 58,500  (the thousands digit goes 9 → 8)
    58,500 − 1,000 = 57,500  (the thousands digit goes 8 → 7)
  3. Write the numbers in order.
    61,500, 60,500, 59,500, 58,500, 57,500

Check. Go the other way from the last number: 57,500 + 1,000 = 58,500. ✓

Watch out. Only the thousands digit changes, unless it is a 9 going up (carry) or a 0 going down (swap). Check the digit before every jump.

Worked example 1.3.3
Count on in 100s from 98,600. Write the next four numbers.

Key words. Counting in steps of 100 means adding 100 again and again. 10, 100, 1,000, 10,000 and 100,000 are powers of 10.

Method. Counting on in 100s means adding 100 each time. Only the hundreds digit changes (unless we carry or swap).

  1. Find the size of each jump. We are counting on in steps of 100, which is 1 hundred.
    Each jump is +100.
  2. Work out the numbers one jump at a time. Always start from the number you have just found.
    98,600 + 100 = 98,700  (the hundreds digit goes 6 → 7)
    98,700 + 100 = 98,800  (the hundreds digit goes 7 → 8)
    98,800 + 100 = 98,900  (the hundreds digit goes 8 → 9)
    98,900 + 100 = 99,000  (9 hundreds + 1 hundred = 10 hundreds: write 0 and carry 1 to the next column)
  3. Write the numbers in order.
    98,700, 98,800, 98,900, 99,000

Check. Go the other way from the last number: 99,000 − 100 = 98,900. ✓

Watch out. Only the hundreds digit changes, unless it is a 9 going up (carry) or a 0 going down (swap). Check the digit before every jump.

Worked example 1.3.4
Count back in 10,000s from 205,000. Write the next three numbers.

Key words. Counting in steps of 10,000 means taking away 10,000 again and again. 10, 100, 1,000, 10,000 and 100,000 are powers of 10.

Method. Counting back in 10,000s means taking away 10,000 each time. Only the ten thousands digit changes (unless we carry or swap).

  1. Find the size of each jump. We are counting back in steps of 10,000, which is 1 ten thousand.
    Each jump is −10,000.
  2. Work out the numbers one jump at a time. Always start from the number you have just found.
    205,000 − 10,000 = 195,000  (0 ten thousands: swap 1 from the next column for 10 ten thousands, then take 1 ten thousand away)
    195,000 − 10,000 = 185,000  (the ten thousands digit goes 9 → 8)
    185,000 − 10,000 = 175,000  (the ten thousands digit goes 8 → 7)
  3. Write the numbers in order.
    195,000, 185,000, 175,000

Check. Go the other way from the last number: 175,000 + 10,000 = 185,000. ✓

Watch out. Only the ten thousands digit changes, unless it is a 9 going up (carry) or a 0 going down (swap). Check the digit before every jump.

Worked example 1.3.5
What is 100,000 more than 478,350?

Method. To find 100,000 more, change the hundred thousands digit by 1. Look out for 9s going up (carrying) and 0s going down (swapping).

  1. Find the hundred thousands digit. 100,000 is one hundred thousand, so we change the hundred thousands digit.
    ThousandsOnes
    HThTThThHTO
    478350
  2. Add 1 to the hundred thousands digit. 100,000 more means 1 more hundred thousand.
    4 + 1 = 5 hundred thousands
  3. Write the new number. The digits that did not change stay the same.
    478,350 + 100,000 = 578,350

Check. Do the opposite: 578,350 − 100,000 = 478,350. ✓

Watch out. Only the digit in the column you are working on changes, unless you carry or swap. Do not change all the digits.

Worked example 1.3.6
What is 1,000 less than 300,000?

Method. To find 1,000 less, change the thousands digit by 1. Look out for 9s going up (carrying) and 0s going down (swapping).

  1. Find the thousands digit. 1,000 is one thousand, so we change the thousands digit.
    ThousandsOnes
    HThTThThHTO
    300000
  2. Take 1 from the thousands digit. There are 0 thousands, so we swap 1 from the next column for 10 thousands. If that next digit is also 0 we swap again. Then take 1 away.
    0 thousands → swap, then 10 − 1 = 9 thousands
  3. Write the new number. The digits that did not change stay the same.
    ThousandsOnes
    HThTThThHTO
    300,000300000
    299,000299000

    300,000 − 1,000 = 299,000

Check. Do the opposite: 299,000 + 1,000 = 300,000. ✓

Watch out. Only the digit in the column you are working on changes, unless you carry or swap. Do not change all the digits.

Worked example 1.3.7
Write the missing numbers in this sequence.   132,000,  ?,  152,000,  ?,  172,000

Method. Find the size of one jump from two numbers you can see. Then use it to fill the gaps.

  1. Find two numbers you know and count the jumps between them. Each jump in the sequence is the same size.
    From 132,000 to 152,000 is 2 jumps.
    The difference is 20,000.
    20,000 ÷ 2 = 10,000
  2. Say which way and how big each jump is. The numbers are getting bigger, so we count on.
    Each jump is +10,000.
  3. Fill in the missing numbers. Add (or take away) one jump from a number you know. Where two gaps are side by side, fill one first and use it for the next.
    Number 2: 132,000 + 10,000 = 142,000
    Number 4: 152,000 + 10,000 = 162,000
  4. Write the missing numbers. Put them in the order they appear.
    142,000, 162,000

Check. Read the whole sequence again and check every jump is +10,000: 132,000, 142,000, 152,000, 162,000, 172,000. ✓

Watch out. Do not just look at the first two numbers. Check the jump is the same all the way along.

Worked example 1.3.8
Here is the start of a sequence: 36,250, 36,350, 36,450, 36,550. What is the rule? Write the next two numbers.

Method. Work out how much each term changes by. If the jump is always the same, that is the rule.

  1. Write the first terms in a place-value table. Look for the one column that changes.
    ThousandsOnes
    TThThHTO
    36,25036250
    36,35036350
    36,45036450
  2. Find the jump between two terms next to each other. The column that changes tells us the size of the jump.
    36,350 − 36,250 = 100 (it goes up)
  3. Check the jump is the same all the way along. A rule has to work for every pair of terms.
    36,350 − 36,250 = 100
    36,450 − 36,350 = 100
    36,550 − 36,450 = 100
  4. Write the rule and the next two terms. Add 100 each time.
    Rule: add 100.
    Next two terms: 36,650, 36,750

Check. 36,550 + 100 = 36,650 and 36,650 + 100 = 36,750. ✓

Watch out. Check more than one pair of terms. One pair is not enough to be sure of the rule.

Worked example 1.3.9
Jack counts on in 10,000s from 120,000 to 200,000. How many jumps does he make?

Method. Find the total distance, then work out how many jumps of 10,000 fit into it.

  1. Find how far it is from the start to the end. Subtract the start from the end.
    200,000 − 120,000 = 80,000
  2. Divide by the size of each jump. Each jump is 10,000.
    80,000 ÷ 10,000 = 8
  3. Write the answer.
    8 jumps of 10,000

Check. 8 × 10,000 = 80,000 and 120,000 + 80,000 = 200,000. ✓

Watch out. Count the jumps, not the numbers you say. Counting the numbers would include the start and give one too many.

Watch out

Do not change every digit. 100,000 less than 640,000 is 540,000, not 630,000 or 539,000. Only the hundred thousands digit changes. Also take care with 9s and 0s: 1,000 less than 300,000 is 299,000, not 200,000.

Exercise 1C  Counting in powers of 10

Non-calculator
1
FCount on. Write the next three numbers each time.
(a)In 10s from 4,570
(b)In 100s from 28,300
(c)In 1,000s from 351,200
(d)In 10,000s from 420,000
2
FCount back. Write the next three numbers each time.
(a)In 10s from 6,080
(b)In 100s from 71,450
(c)In 1,000s from 530,000
(d)In 100,000s from 900,000
3
FWork out each number.
(a)10 more than 7,995
(b)100 more than 54,950
(c)1,000 more than 249,500
(d)10,000 more than 395,000
(e)100,000 more than 299,999
(f)10,000 more than 899,000
4
FWork out each number.
(a)10 less than 5,000
(b)100 less than 30,050
(c)1,000 less than 100,000
(d)10,000 less than 205,000
(e)100,000 less than 640,000
(f)1,000 less than 700,500
5
FWrite the missing numbers in each sequence.
(a)?,  7,260,  7,270,  ?,  7,290
(b)850,000,  ?,  ?,  550,000,  450,000
(c)395,000,  ?,  397,000,  398,000,  ?,  ?
(d)600,000,  ?,  800,000,  ?,  1,000,000
(e)4,000,  ?,  ?,  3,700
6
FLeo is counting on in the same-sized steps. Write the numbers that are missing from the number line.
240,000??280,000??320,000
7
FFind the rule for each sequence. Then write the next two numbers.
(a)5,320,  5,420,  5,520,  5,620…
(b)800,000,  700,000,  600,000,  500,000…
(c)204,000,  214,000,  224,000,  234,000…
(d)8,090,  8,080,  8,070,  8,060…
8
FWrite the missing number in each box.
(a)245,600 + ? = 345,600
(b)? − 1,000 = 87,500
(c)630,000 − ? = 620,000
(d)? + 100 = 4,000
9
PSA video has been watched 48,500 times. It gets 10,000 more views every day. On which day does it first have more than 100,000 views?
10
PSHow many jumps are there?
(a)How many steps of 10,000 from 120,000 to 200,000?
(b)How many steps of 100 from 3,500 to 4,200?
(c)How many steps of 100,000 from 150,000 to 650,000?
11
PSThe mileage counter on a car shows 99,995 miles.
(a)What will it show after 10 more miles?
(b)Another car shows 49,950 miles. What will it show after 100 more miles?
12
PSA water tank holds 25,000 litres. Water runs out at 1,000 litres each minute.
(a)How much water is left after 7 minutes?
(b)How many minutes does it take for the tank to be empty?
13
RSam says, “1,000 less than 300,000 is 200,000.” Spot his mistake and give the correct answer.
14
RIs this always, sometimes or never true?
“When you add 1,000 to a number, only the thousands digit changes.”
15
RZainab counts on in 10,000s from 5,000. Will she say 100,000? Prove it.
16
RA sequence starts at 7,125. Each number is 1,000 more than the one before. What is the first number in the sequence that is more than 50,000? How many jumps is that?
1.4

Negative numbers: temperatures, depths and bank balances

Year 5
Negative numbers in context, Counting through zero, Differences across zero

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Negative numbers: temperatures, depths and bank balancesComing soon

Numbers below zero are called negative numbers. We use them in real life. When it is very cold, the temperature can go below zero: 5 degrees below zero is written −5°C. When we measure heights and depths, sea level is zero. A diver 15 metres under the sea is at −15 m. In a bank account, a balance of −£30 means the account is overdrawn: you owe the bank £30. In a building, floors below the ground floor can be −1, −2 and so on.

−15−10−5051015Leeds−15−10−5051015Bath−15−10−5051015Cork
Three thermometers: −12°C, 3°C and 9°C. Each small mark is 1 degree.
sea level (0 m)−50−40−30−20−100102030Lighthouse topBoatDiverWreck
Sea level is 0 m. Heights above it are positive. Depths below it are negative.

On a number line, zero is in the middle. Numbers to the right are bigger. Numbers to the left are smaller, so the further left a number is, the smaller it is. −20 is smaller than −5.

−25−20−15−10−50510152025−20−512
−20 < −5 < 12. The numbers increase as you go right.

Counting through zero. If you count back in 4s from 10, you say 6, 2, −2, −6… When a jump goes past zero, split it into two parts. To work out 2 − 4, go down 2 to reach 0, then 2 more: that is −2. Going up works the same way: −3 + 7 is 3 up to reach 0, then 4 more, which is 4.

The difference across zero. To find how far apart a negative and a positive number are, add their distances from zero. From −9 up to 6 is 9 + 6 = 15. If both numbers are below zero, take the smaller distance from the bigger: from −9 to −2 is 9 − 2 = 7.

Key words. A negative number is less than zero. Overdrawn means the bank balance is below zero. The difference between two numbers is how far apart they are on a number line.

Key ideas

  • Negative numbers are less than zero: −1, −2, −3… Used for temperatures, depths below sea level, overdrawn bank balances and floors below ground.
  • On a number line, the further left, the smaller. −20 < −5.
  • Counting through zero: split the jump into the part that reaches 0 and the part that goes past it.
  • Difference across zero: add the distances from zero (−9 to 6 is 9 + 6 = 15).
  • Difference when both are below zero: subtract the distances (−9 to −2 is 9 − 2 = 7).
Worked example 1.4.1
What temperature does this thermometer show?
−10−505101520

Method. Find the numbered mark nearest the top of the red liquid, then count the small marks to the top.

  1. Look at the numbers on the scale. The scale is numbered every 5 degrees. The small marks are 1 degree each.
    Big numbers: ..., −5, 0, 5, 10, ...
  2. Find the numbered mark just below the top of the red. The top of the red is between −10 and −5.
    The mark below is −10.
  3. Count the small marks above it. Each small mark is 1 degree.
    3 small marks above −10: −10 + 3 = −7

Check. Count from 0 instead: the top of the red is 7 small marks below 0, so the temperature is −7°C. ✓

Watch out. Going up the scale the numbers get bigger. Below zero, the number nearest the bottom is the smallest.

Worked example 1.4.2
Count back in 4s from 14. Write the next six numbers.

Key words. A negative number is less than zero. It has a minus sign in front, like −4.

Method. Counting back in 4s means taking away 4 each time. A number line helps when we go through zero.

  1. Draw a number line. Numbers to the left of 0 are negative (below zero). Numbers to the right are positive.
    −12−8−40481216
  2. Jump back 4 each time, starting from 14. When a jump goes past zero, split it into the part that reaches zero and the part that goes beyond.
    14 − 4 = 10
    10 − 4 = 6
    6 − 4 = 2
    2 down 4: go down 2 to reach 0, then 2 more below zero → −2
    −2 down 4: start at or below zero and go down 4 more → −6
    −6 down 4: start at or below zero and go down 4 more → −10
  3. Write the numbers in order.
    10, 6, 2, −2, −6, −10

Check. Go the other way from the last number: −10 + 4 = −6. ✓

Watch out. After 0 comes −1, not 1. Below zero the numbers count down: −1, −2, −3…

Worked example 1.4.3
Count on in 10s from −35. Write the next five numbers.

Key words. A negative number is less than zero. It has a minus sign in front, like −4.

Method. Counting on in 10s means adding 10 each time. A number line helps when we go through zero.

  1. Draw a number line. Numbers to the left of 0 are negative (below zero). Numbers to the right are positive.
    −40−30−20−1001020
  2. Jump on 10 each time, starting from −35. When a jump goes past zero, split it into the part that reaches zero and the part that goes beyond.
    −35 up 10: start below zero and go up 10 → −25
    −25 up 10: start below zero and go up 10 → −15
    −15 up 10: start below zero and go up 10 → −5
    −5 up 10: go up 5 to reach 0, then 5 more → 5
    5 + 10 = 15
  3. Write the numbers in order.
    −25, −15, −5, 5, 15

Check. Go the other way from the last number: 15 − 10 = 5. ✓

Watch out. After 0 comes −1, not 1. Below zero the numbers count down: −1, −2, −3…

Worked example 1.4.4
The temperature is 5°C. It falls by 12°C. What is the new temperature?

Method. Draw a number line, start at 5 and jump down 12. When you pass 0 the numbers change between positive and negative.

  1. Show the start on a number line. This lets us see where zero is.
    −8−6−4−202465−12
  2. Go down 12. Split the jump into two parts if it crosses zero: the part that reaches 0, then the part that goes past it.
    5 down 12: go down 5 to reach 0, then 7 more below zero → −7
  3. Write the answer. This is the new temperature.
    −7°C

Check. Do the opposite: −7 + 12 = 5. ✓

Watch out. Going down past zero gives a negative number. Going up from a negative number gets closer to zero.

Worked example 1.4.5
At night the temperature is −9°C. By midday it has risen by 14°C. What is the temperature at midday?

Method. Draw a number line, start at −9 and jump up 14. When you pass 0 the numbers change between positive and negative.

  1. Show the start on a number line. This lets us see where zero is.
    −10−8−6−4−20246−9+14
  2. Go up 14. Split the jump into two parts if it crosses zero: the part that reaches 0, then the part that goes past it.
    −9 up 14: go up 9 to reach 0, then 5 more → 5
  3. Write the answer. This is the new temperature.
    5°C

Check. Do the opposite: 5 − 14 = −9. ✓

Watch out. Going down past zero gives a negative number. Going up from a negative number gets closer to zero.

Worked example 1.4.6
How many degrees warmer is 6°C than −9°C?

Method. The difference between two numbers is how far apart they are on a number line.

  1. Mark both numbers on a number line. Seeing the gap helps.
    −10−8−6−4−202468−9615
  2. Count the gap. One number is below zero and one is above. Count up to zero first, then on to the other number.
    −9 up to 0 is 9.
    0 up to 6 is 6.
    9 + 6 = 15
  3. Write the answer.
    15°C

Check. Start at −9 and go up 15: −9 + 15 = 6. ✓

Watch out. Do not just subtract the digits when one number is negative. Go through zero: −4 and 5 are 9 apart, not 1.

Worked example 1.4.7
Write these numbers in order, smallest first:   −12,   5,   −3,   0,   −20,   8

Method. On a number line, numbers further to the left are smaller. Mark each number, then read them off from left to right.

  1. Put the numbers on a number line. The line shows which are below zero.
    −20−16−12−8−4048
  2. Read from left to right. Left is smallest, right is biggest.
    −20, −12, −3, 0, 5, 8
  3. Write them smallest first. Check you have used every number once.
    −20, −12, −3, 0, 5, 8

Check. The numbers below zero are the smallest. Of those, the one with the biggest digit (like −9) is furthest from zero, so it is the smallest. ✓

Watch out. −9 is smaller than −2. The further below zero, the smaller the number.

Worked example 1.4.8
Dev’s bank balance is −£45. He pays in £120. What is his new balance?

Key words. The balance is how much money is in a bank account. Overdrawn means the balance is below zero.

Method. A positive balance means the account has money in it. A negative balance means the bank is owed money (overdrawn). Paying in adds money.

  1. Write the balance as a positive or negative number. Money owed is below zero.
    Balance now: −£45
  2. Add £120. Split the move if it crosses zero.
    −£45 up £120: go up £45 to reach 0, then £75 more → £75
  3. Write the new balance. If it is negative, the account is overdrawn.
    £75

Check. Do the opposite: £75 − £120 = −£45. ✓

Watch out. Being −£40 means you owe £40. Paying in £40 only gets you back to £0.

Worked example 1.4.9
A submarine is at −120 m (120 m below sea level). It rises 45 m. Where is it now?

Method. Draw a number line, start at −120 and jump up 45. When you pass 0 the numbers change between positive and negative.

  1. Show the start on a number line. This lets us see where zero is.
    −120−100−80−60−40−200−120+45
  2. Go up 45. Split the jump into two parts if it crosses zero: the part that reaches 0, then the part that goes past it.
    −120 up 45: start below zero and go up 45 → −75
  3. Write the answer. This is the new depth.
    −75 m

Check. Do the opposite: −75 − 45 = −120. ✓

Watch out. Going down past zero gives a negative number. Going up from a negative number gets closer to zero.

Worked example 1.4.10
A cliff top is 35 m above sea level. A cave is 18 m below sea level. How far is it from the cliff top to the cave?

Method. The difference between two numbers is how far apart they are on a number line.

  1. Mark both numbers on a number line. Seeing the gap helps.
    −20−10010203040−183553
  2. Count the gap. One number is below zero and one is above. Count up to zero first, then on to the other number.
    −18 up to 0 is 18.
    0 up to 35 is 35.
    18 + 35 = 53
  3. Write the answer.
    53 m

Check. Start at −18 and go up 53: −18 + 53 = 35. ✓

Watch out. Do not just subtract the digits when one number is negative. Go through zero: −4 and 5 are 9 apart, not 1.

Watch out

A negative number with a bigger digit is a smaller number: −20 is less than −5, because it is further below zero. And do not just subtract the digits when a number is negative. The gap between −4 and 5 is 9, not 1. Always go through zero.

Exercise 1D  Negative numbers

Non-calculator
1
PSThe thermometers show the temperature in four cities one morning.
−15−10−5051015Edinburgh−15−10−5051015Cardiff−15−10−5051015Reykjavik−15−10−5051015Madrid
(a)Which city is the coldest?
(b)Which city is the warmest?
(c)How many degrees warmer is Cardiff than Edinburgh?
(d)What is the difference in temperature between Madrid and Reykjavik?
(e)Write the cities in order, coldest first.
2
FWhat temperature does the thermometer show?
−10−505101520
3
FWrite the missing numbers in the boxes on the number line.
−40?−20?0?20?40
4
FCount on or back. Write the next five numbers each time.
(a)Count back in 3s from 10.
(b)Count on in 5s from −22.
(c)Count back in 10s from 25.
(d)Count on in 4s from −18.
5
FWrite < or > in each box.
(a)−3  [ ? ]  2
(b)−17  [ ? ]  −7
(c)0  [ ? ]  −1
(d)−25  [ ? ]  −52
(e)−100  [ ? ]  10
(f)−6  [ ? ]  −60
6
FWrite each set of numbers in order.
(a)−14,  6,  −2,  −20,  9,  0  (smallest first)
(b)−35,  −3,  −53,  5,  35  (biggest first)
7
FWhat is the new temperature?
(a)It is 6°C. It falls by 11°C.
(b)It is −3°C. It rises by 9°C.
(c)It is −12°C. It rises by 5°C.
(d)It is 4°C. It falls by 15°C.
8
FFind the difference between the two temperatures.
(a)−4°C and 9°C
(b)−13°C and −2°C
(c)−21°C and 6°C
(d)5°C and −17°C
(e)−30°C and −5°C
9
PSZainab’s bank statement is shown below.
What happenedMoney inMoney outBalance
Opening balance−£30
Birthday money paid in£85£55
Bought a book£60−£5
Pocket money paid in£20?
Bought a game£45?
(a)What is her balance after the pocket money is paid in?
(b)What is her balance after she buys the game?
(c)How much must she pay in to get her balance back to £0?
10
PSThe picture shows a lighthouse, a boat, a diver and a wreck.
sea level (0 m)−50−40−30−20−100102030Lighthouse topBoatDiverWreck
(a)How far is the wreck below the boat?
(b)How far is it from the top of the lighthouse to the diver?
(c)The diver dives another 12 m. What is her position now?
11
PSA building has floors numbered from −2 (the car park) to 8.
(a)A lift starts on floor 5 and goes down 8 floors. Which floor is it on now?
(b)A cleaner goes from floor −2 up to floor 6. How many floors does she go up?
12
PSA freezer at −18°C is switched off. The temperature inside rises by 3°C every hour. After how many hours is it first above 0°C?
13
PSAt midnight the temperature is −9°C. By 6 a.m. it has risen by 4°C. By noon it has risen by another 11°C. By 6 p.m. it has fallen by 8°C.
(a)What is the temperature at noon?
(b)What is the temperature at 6 p.m.?
(c)What is the difference between the lowest and the highest temperatures of the day?
14
RThe temperature rises from −6°C to 4°C. Aisha says it has risen by 2°C. What mistake has she made? What is the correct answer?
15
RIs this always, sometimes or never true?
“If you take a number away from 5, the answer is positive.”
16
RWhich one is different?   −7°C    7°C below zero    minus seven degrees    7°C above zero
17
RTwo temperatures are 14 degrees apart. One of them is −5°C. What could the other temperature be? Find both answers.
1.5

Rounding and estimating

Year 5
Round numbers to 10, 100, 1,000, 10,000 and 100,000, Estimate and solve number problems

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Rounding and estimatingComing soon

Sometimes we do not need an exact number. A news report might say “about 350,000 people live in the city” when the real number is 347,862. Changing a number to a nearby, simpler number is called rounding. We can round to the nearest 10, 100, 1,000, 10,000 or 100,000.

Look at 347,862 on a number line. To the nearest 1,000 it is between 347,000 and 348,000. The halfway point is 347,500. 347,862 is past halfway, so we round up to 348,000.

347,000347,500348,000halfway347,862
347,862 to the nearest 1,000: past halfway (347,500), so round up to 348,000.

Here is the rule. Look at the digit to the right of the place you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down. All the digits to the right become zeros. When a number is exactly halfway, such as 450,000 to the nearest 100,000, we always round up.

340,000345,000350,000halfway347,862
347,862 to the nearest 10,000: the thousands digit is 7, so round up to 350,000.
300,000350,000400,000halfway347,862
347,862 to the nearest 100,000: the ten thousands digit is 4, so round down to 300,000.

Look out for 9s. When you round up a 9, it becomes 10 and carries. 99,960 to the nearest 100 is 100,000. Which numbers round to a given number? To the nearest 1,000, the numbers from 6,500 to 7,499 all round to 7,000. 6,500 is halfway and rounds up. 7,500 is halfway and rounds up to 8,000, so it is not included.

6,0006,5007,0007,5008,000these round to 7,000
Every whole number from 6,500 to 7,499 rounds to 7,000.

Estimating. To estimate an answer, round the numbers first and then do the easy calculation. 48,920 + 31,150 to the nearest 10,000 is 50,000 + 30,000 = 80,000. The exact answer will be close to 80,000. An estimate is also a good way to check that an answer is sensible.

Key words. To round a number is to change it to a nearby number that is easier to use. An estimate is a sensible answer that is close to the exact one. ≈ means “is about equal to”.

Key ideas

  • Look at the digit just to the right of the place you are rounding to.
  • 5 or more: round up. 4 or less: round down. Digits to the right become zeros.
  • Halfway always rounds up: 450,000 to the nearest 100,000 is 500,000.
  • A 9 can carry: 99,960 to the nearest 100 is 100,000.
  • Always round the original number. Do not round twice.
  • To estimate, round each number first and then calculate.
Worked example 1.5.1
Round 347,862 to the nearest 10.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 10 that 347,862 is between. Rounding to the nearest 10 means choosing the closest multiple of 10.
    347,860  <  347,862  <  347,870
  2. Picture it on a number line. The halfway point between 347,860 and 347,870 is 347,865.
    347,860347,865347,870halfway347,862
  3. Look at the ones digit (the digit just to the right of the tens digit). This digit tells us if we are past halfway.
    The ones digit is 2.
  4. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    2 is 4 or less, so round down.
  5. Write the rounded number. All the digits to the right of the tens column become zeros.
    347,862 ≈ 347,860 (to the nearest 10)

Check. Distances: 347,862 − 347,860 = 2 and 347,870 − 347,862 = 8. 347,860 is the nearer one. ✓

Watch out. Only the digit just to the right decides. Do not look at digits further along.

Worked example 1.5.2
Round 73,468 to the nearest 100.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 100 that 73,468 is between. Rounding to the nearest 100 means choosing the closest multiple of 100.
    73,400  <  73,468  <  73,500
  2. Look at the tens digit (the digit just to the right of the hundreds digit). This digit tells us if we are past halfway.
    The tens digit is 6.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    6 is 5 or more, so round up.
  4. Write the rounded number. All the digits to the right of the hundreds column become zeros.
    73,468 ≈ 73,500 (to the nearest 100)

Check. Distances: 73,468 − 73,400 = 68 and 73,500 − 73,468 = 32. 73,500 is the nearer one. ✓

Watch out. Only the digit just to the right decides. Do not look at digits further along.

Worked example 1.5.3
Round 268,450 to the nearest 1,000.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 1,000 that 268,450 is between. Rounding to the nearest 1,000 means choosing the closest multiple of 1,000.
    268,000  <  268,450  <  269,000
  2. Look at the hundreds digit (the digit just to the right of the thousands digit). This digit tells us if we are past halfway.
    The hundreds digit is 4.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    4 is 4 or less, so round down.
  4. Write the rounded number. All the digits to the right of the thousands column become zeros.
    268,450 ≈ 268,000 (to the nearest 1,000)

Check. Distances: 268,450 − 268,000 = 450 and 269,000 − 268,450 = 550. 268,000 is the nearer one. ✓

Watch out. Only the digit just to the right decides. Do not look at digits further along.

Worked example 1.5.4
Round 84,730 to the nearest 10,000.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 10,000 that 84,730 is between. Rounding to the nearest 10,000 means choosing the closest multiple of 10,000.
    80,000  <  84,730  <  90,000
  2. Look at the thousands digit (the digit just to the right of the ten thousands digit). This digit tells us if we are past halfway.
    The thousands digit is 4.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    4 is 4 or less, so round down.
  4. Write the rounded number. All the digits to the right of the ten thousands column become zeros.
    84,730 ≈ 80,000 (to the nearest 10,000)

Check. Distances: 84,730 − 80,000 = 4,730 and 90,000 − 84,730 = 5,270. 80,000 is the nearer one. ✓

Watch out. Only the digit just to the right decides. Do not look at digits further along.

Worked example 1.5.5
Round 286,450 to the nearest 100,000.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 100,000 that 286,450 is between. Rounding to the nearest 100,000 means choosing the closest multiple of 100,000.
    200,000  <  286,450  <  300,000
  2. Look at the ten thousands digit (the digit just to the right of the hundred thousands digit). This digit tells us if we are past halfway.
    The ten thousands digit is 8.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    8 is 5 or more, so round up.
  4. Write the rounded number. All the digits to the right of the hundred thousands column become zeros.
    286,450 ≈ 300,000 (to the nearest 100,000)

Check. Distances: 286,450 − 200,000 = 86,450 and 300,000 − 286,450 = 13,550. 300,000 is the nearer one. ✓

Watch out. Only the digit just to the right decides. Do not look at digits further along.

Worked example 1.5.6
Round 99,960 to the nearest 100.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 100 that 99,960 is between. Rounding to the nearest 100 means choosing the closest multiple of 100.
    99,900  <  99,960  <  100,000
  2. Look at the tens digit (the digit just to the right of the hundreds digit). This digit tells us if we are past halfway.
    The tens digit is 6.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    6 is 5 or more, so round up.
  4. Write the rounded number. All the digits to the right of the hundreds column become zeros.
    99,960 ≈ 100,000 (to the nearest 100)

Check. Distances: 99,960 − 99,900 = 60 and 100,000 − 99,960 = 40. 100,000 is the nearer one. ✓

Watch out. A 9 can carry: when you round up a 9 it becomes 10, so the next digit goes up too.

Worked example 1.5.7
Round 450,000 to the nearest 100,000.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Look at the digit to the right of the one you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

  1. Find the two multiples of 100,000 that 450,000 is between. Rounding to the nearest 100,000 means choosing the closest multiple of 100,000.
    400,000  <  450,000  <  500,000
  2. Look at the ten thousands digit (the digit just to the right of the hundred thousands digit). This digit tells us if we are past halfway.
    The ten thousands digit is 5.
  3. Decide: round up or round down? 5 or more: round up. 4 or less: round down.
    5 is 5 or more, so round up.
  4. Write the rounded number. All the digits to the right of the hundred thousands column become zeros.
    450,000 ≈ 500,000 (to the nearest 100,000)

Check. Distances: 450,000 − 400,000 = 50,000 and 500,000 − 450,000 = 50,000. 500,000 is the one we choose when exactly halfway (halfway rounds up). ✓

Watch out. Only look at the digit just to the right. Do not round twice. Halfway always rounds up.

Worked example 1.5.8
Round 542,981 to the nearest 10, 100, 1,000, 10,000 and 100,000.

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. Round the number five times, one place at a time. Always go back to the original number, not to the number you just rounded.

  1. Round to the nearest 10. Look at the ones digit, 1. It is 4 or less, so round down.
    542,981 ≈ 542,980
  2. Round to the nearest 100. Look at the tens digit, 8. It is 5 or more, so round up.
    542,981 ≈ 543,000
  3. Round to the nearest 1,000. Look at the hundreds digit, 9. It is 5 or more, so round up.
    542,981 ≈ 543,000
  4. Round to the nearest 10,000. Look at the thousands digit, 2. It is 4 or less, so round down.
    542,981 ≈ 540,000
  5. Round to the nearest 100,000. Look at the ten thousands digit, 4. It is 4 or less, so round down.
    542,981 ≈ 500,000
  6. Put the answers in a table. Seeing them together shows how the numbers change.
    NearestDigit looked atRounded
    101542,980
    1008543,000
    1,0009543,000
    10,0002540,000
    100,0004500,000

Check. Each rounded number should be close to 542,981. The bigger the place, the further away it can be. ✓

Watch out. Always round the original number each time. Rounding a rounded number can give the wrong answer.

Worked example 1.5.9
What are the smallest and largest whole numbers that round to 7,000 when rounded to the nearest 1,000?

Key words. To round a number is to change it to a nearby number that is easier to use. ≈ means “is about equal to”.

Method. The numbers that round to 7,000 are all the numbers that are closer to 7,000 than to any other multiple of 1,000, and also the halfway number below it. Find the halfway points on each side.

  1. Find the multiples of 1,000 on each side. The numbers either side are one step away.
    6,000, 7,000, 8,000
  2. Find the halfway point below. Halfway is half of 1,000 = 500 below 7,000. Halfway rounds up, so this number does round to 7,000.
    7,000 − 500 = 6,500 (smallest)
  3. Find the halfway point above. The halfway number above is 7,500, but halfway rounds up, so it goes to 8,000. So the largest is 1 less.
    7,500 − 1 = 7,499 (largest)
  4. Show it on a number line. The shaded part is every number that rounds to 7,000. The solid dot is included; the open dot is not.
    6,0006,5007,0007,5008,000these round to 7,000

Check. 6,500 rounds up to 7,000 ✓. 6,499 rounds down to 6,000. 7,499 rounds down to 7,000 ✓. 7,500 rounds up to 8,000.

Watch out. The halfway number at the bottom is included but the halfway number at the top is not, because halfway rounds up.

Worked example 1.5.10
Estimate 48,920 + 31,150 by rounding each number to the nearest 10,000.

Key words. An estimate is a sensible answer that is close to the exact one. We find it by rounding first.

Method. Round both numbers to the nearest 10,000, then do the easy calculation.

  1. Round the first number. Look at the digit just to the right of the ten thousands column.
    48,920 ≈ 50,000
  2. Round the second number. Do the same.
    31,150 ≈ 30,000
  3. Do the easy calculation. Rounded numbers are quick to add and take away.
    50,000 + 30,000 = 80,000

Check. The exact answer is 80,070, which is close to 80,000. ✓

Watch out. An estimate is not exact. It tells you roughly how big the answer should be.

Worked example 1.5.11
Estimate 612,480 − 187,350 by rounding each number to the nearest 100,000.

Key words. An estimate is a sensible answer that is close to the exact one. We find it by rounding first.

Method. Round both numbers to the nearest 100,000, then do the easy calculation.

  1. Round the first number. Look at the digit just to the right of the hundred thousands column.
    612,480 ≈ 600,000
  2. Round the second number. Do the same.
    187,350 ≈ 200,000
  3. Do the easy calculation. Rounded numbers are quick to add and take away.
    600,000 − 200,000 = 400,000

Check. The exact answer is 425,130, which is close to 400,000. ✓

Watch out. An estimate is not exact. It tells you roughly how big the answer should be.

Watch out

Only look at the digit just to the right. To round 3,459 to the nearest 10, the ones digit is 9, so round up to 3,460. Do not round the 9 up to make the 5 a 6 and then round again to 3,500. And 5 rounds up: 3,465 to the nearest 10 is 3,470.

Exercise 1E  Rounding and estimating

Non-calculator
1
FRound each number to the nearest 10.
(a)74
(b)365
(c)2,384
(d)15,495
(e)70,001
(f)428,555
2
FRound each number to the nearest 100.
(a)347
(b)3,650
(c)62,238
(d)49,950
(e)128,449
(f)999,960
3
FRound each number to the nearest 1,000.
(a)4,280
(b)36,500
(c)79,999
(d)252,499
(e)499,501
(f)910,350
4
FRound each number to the nearest 10,000.
(a)38,200
(b)65,000
(c)124,999
(d)449,500
(e)895,001
(f)7,300
5
FRound each number to the nearest 100,000.
(a)340,000
(b)450,000
(c)249,999
(d)650,100
(e)85,000
(f)960,500
6
FRound 354,628 to the nearest:
(a)10
(b)100
(c)1,000
(d)10,000
(e)100,000
7
FThe number line shows 72,640. Use it to round 72,640 to the nearest 1,000.
72,00072,50073,000halfway72,640
8
FThe arrow points to a number. Round that number to the nearest 10,000.
40,00045,00050,000?
9
FThe table shows how many people live in four towns. Round each number to the nearest 10,000.
TownPeople
Fenby43,816
Grimsworth128,450
Hale96,500
Ingleby252,049
(a)Fenby
(b)Grimsworth
(c)Hale
(d)Ingleby
10
RWhich of these numbers does not round to 60,000 when rounded to the nearest 10,000?   55,000   64,999   65,000   59,500
11
PSWhich digits could go in the box so that 6?,500 rounds to 70,000 when rounded to the nearest 10,000?
12
RFind the smallest and the largest whole number that round to each number.
(a)250 (to the nearest 10)
(b)7,000 (to the nearest 1,000)
(c)300,000 (to the nearest 100,000)
13
PSEstimate each answer by rounding the numbers first.
(a)6,214 + 2,788  (round to the nearest 1,000)
(b)48,920 − 21,350  (round to the nearest 10,000)
(c)418,200 + 189,700  (round to the nearest 100,000)
14
RAmira adds 38,420 + 41,690. She gets 70,110. Use an estimate to show that her answer cannot be right. What should the answer be?
15
PSA report says the crowd at a match was 42,000 to the nearest 1,000. What is the smallest and the largest number of people who could have been there?
16
PSA car costs £14,950. Round the price to the nearest:
(a)£1,000
(b)£100
(c)£10,000
17
RLeo rounds 349,500 to the nearest 100,000. He says, “349,500 rounds to 350,000, and that rounds to 400,000.” Is he right? Explain.
18
RIs this always, sometimes or never true?
“A number rounded to the nearest 10 is the same as when it is rounded to the nearest 100.”
19
RZainab says, “250,000 is closer to 200,000 than to 300,000.” Is she right? What does 250,000 round to, to the nearest 100,000?
1.6

Roman numerals to 1,000 and years

Year 5
Roman numerals to 1,000, Years in Roman numerals

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Roman numerals to 1,000 and yearsComing soon

In Year 4 you learned the Roman symbols I, V, X, L and C. To read numbers up to 1,000 you need two more: D = 500 and M = 1,000.

I1V5X10L50C100D500M1,000
The seven Roman symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000.

The rules. (1) Same symbols add up: XXX = 30. (2) A smaller symbol after a bigger one is added: DC = 500 + 100 = 600. (3) A smaller symbol before a bigger one is taken away: CM = 1,000 − 100 = 900. (4) Only I, X and C can be taken away, and only from the next two bigger symbols: I before V or X, X before L or C, C before D or M. (5) Never write the same symbol more than three times in a row. To write a number, do the thousands first, then the hundreds, then the tens, then the ones.

OnesRomanTensRomanHundredsRoman
1I10X100C
2II20XX200CC
3III30XXX300CCC
4IV40XL400CD
5V50L500D
6VI60LX600DC
7VII70LXX700DCC
8VIII80LXXX800DCCC
9IX90XC900CM
The building blocks. 1,000 is M, 2,000 is MM, 3,000 is MMM.

Years. Roman numerals are still used for years on buildings, films and TV programmes. The year 1999 is M + CM + XC + IX = MCMXCIX. The year 2026 is MM + XX + VI = MMXXVI. The Romans had no symbol for zero, so a zero in a number is simply left out: 2,006 has no tens or hundreds, so it is MMVI.

MDCCCXCVA plaque on an old town hall
MDCCCXCV = 1,000 + 500 + 300 + 90 + 5 = 1895.

Key words. A numeral is a symbol for a number. Roman numerals use the letters I, V, X, L, C, D and M.

Key ideas

  • I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000.
  • Smaller after bigger: add. Smaller before bigger: take away (IV, IX, XL, XC, CD, CM).
  • Never more than three of the same symbol in a row.
  • Write thousands, then hundreds, then tens, then ones: 1,994 = M + CM + XC + IV = MCMXCIV.
  • A zero is left out. There is no Roman symbol for zero.
Worked example 1.6.1
What number is CDXLVII?

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the Roman numeral into groups, write the value of each group, then add them up.

  1. Split the numeral into groups, reading from the left. A small symbol in front of a bigger one (like CM, XC or IV) is taken away. Otherwise just add.
    CD = 500 − 100 = 400  (small symbol in front, so take it away)
    XL = 50 − 10 = 40  (small symbol in front, so take it away)
    V = 5
    I = 1
    I = 1
  2. Add the values. Add the biggest groups first.
    400 + 40 + 5 + 1 + 1 = 447
  3. Write the answer.
    447

Check. Write 447 in Roman numerals: CD + XL + VII = CDXLVII. ✓

Watch out. Read from the left. A small symbol is only taken away when it comes BEFORE a bigger one: IX is 9 but XI is 11.

Worked example 1.6.2
A film ends with the year MMXXVI. What year is that?

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the Roman numeral into groups, write the value of each group, then add them up.

  1. Split the numeral into groups, reading from the left. A small symbol in front of a bigger one (like CM, XC or IV) is taken away. Otherwise just add.
    M = 1,000
    M = 1,000
    X = 10
    X = 10
    V = 5
    I = 1
  2. Add the values. Add the biggest groups first.
    1,000 + 1,000 + 10 + 10 + 5 + 1 = 2,026
  3. Write the answer.
    2026

Check. Write 2,026 in Roman numerals: MM + XX + VI = MMXXVI. ✓

Watch out. Read from the left. A small symbol is only taken away when it comes BEFORE a bigger one: IX is 9 but XI is 11.

Worked example 1.6.3
Write 649 in Roman numerals.

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the number into thousands, hundreds, tens and ones. Write each part in Roman numerals, then put them side by side (biggest first).

  1. Split the number into thousands, hundreds, tens and ones. Roman numerals are built one part at a time, biggest first.
    649 = 600 + 40 + 9
  2. Write 600 in Roman numerals. D is 500; 400 is CD (100 before 500) and 900 is CM (100 before 1,000).
    600 = DC
  3. Write 40 in Roman numerals. 40 is XL (10 before 50) and 90 is XC (10 before 100).
    40 = XL
  4. Write 9 in Roman numerals. 4 is IV (1 before 5) and 9 is IX (1 before 10).
    9 = IX
  5. Put the parts side by side, biggest first. Thousands on the left, then hundreds, tens and ones.
    DC + XL + IX = DCXLIX

Check. Read it back: 500 + 100 + 40 + 9 = 649. ✓

Watch out. Never write the same symbol more than three times in a row. 4 is IV, not IIII; 40 is XL; 400 is CD; 900 is CM.

Worked example 1.6.4
Write the year 1994 in Roman numerals.

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the number into thousands, hundreds, tens and ones. Write each part in Roman numerals, then put them side by side (biggest first).

  1. Split the number into thousands, hundreds, tens and ones. Roman numerals are built one part at a time, biggest first.
    1,994 = 1,000 + 900 + 90 + 4
  2. Write 1,000 in Roman numerals. M is 1,000.
    1,000 = M
  3. Write 900 in Roman numerals. D is 500; 400 is CD (100 before 500) and 900 is CM (100 before 1,000).
    900 = CM
  4. Write 90 in Roman numerals. 40 is XL (10 before 50) and 90 is XC (10 before 100).
    90 = XC
  5. Write 4 in Roman numerals. 4 is IV (1 before 5) and 9 is IX (1 before 10).
    4 = IV
  6. Put the parts side by side, biggest first. Thousands on the left, then hundreds, tens and ones.
    M + CM + XC + IV = MCMXCIV

Check. Read it back: 1,000 + 900 + 90 + 4 = 1,994. ✓

Watch out. Never write the same symbol more than three times in a row. 4 is IV, not IIII; 40 is XL; 400 is CD; 900 is CM.

Worked example 1.6.5
The Battle of Hastings was in 1066. Write the year in Roman numerals.

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the number into thousands, hundreds, tens and ones. Write each part in Roman numerals, then put them side by side (biggest first).

  1. Split the number into thousands, hundreds, tens and ones. Roman numerals are built one part at a time, biggest first.
    1,066 = 1,000 + 60 + 6
  2. Write 1,000 in Roman numerals. M is 1,000.
    1,000 = M
  3. Write 60 in Roman numerals. 40 is XL (10 before 50) and 90 is XC (10 before 100).
    60 = LX
  4. Write 6 in Roman numerals. 4 is IV (1 before 5) and 9 is IX (1 before 10).
    6 = VI
  5. Put the parts side by side, biggest first. Thousands on the left, then hundreds, tens and ones.
    M + LX + VI = MLXVI

Check. Read it back: 1,000 + 50 + 10 + 5 + 1 = 1,066. ✓

Watch out. Never write the same symbol more than three times in a row. 4 is IV, not IIII; 40 is XL; 400 is CD; 900 is CM.

Worked example 1.6.6
A plaque on a town hall says MDCCCXCV. In which year was it built?
MDCCCXCV

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Split the Roman numeral into groups, write the value of each group, then add them up.

  1. Split the numeral into groups, reading from the left. A small symbol in front of a bigger one (like CM, XC or IV) is taken away. Otherwise just add.
    M = 1,000
    D = 500
    C = 100
    C = 100
    C = 100
    XC = 100 − 10 = 90  (small symbol in front, so take it away)
    V = 5
  2. Add the values. Add the biggest groups first.
    1,000 + 500 + 100 + 100 + 100 + 90 + 5 = 1,895
  3. Write the answer.
    1895

Check. Write 1,895 in Roman numerals: M + DCCC + XC + V = MDCCCXCV. ✓

Watch out. Read from the left. A small symbol is only taken away when it comes BEFORE a bigger one: IX is 9 but XI is 11.

Worked example 1.6.7
Work out DLXII + CXXXVIII. Give your answer in Roman numerals.

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Change the Roman numerals into numbers, do the calculation, then change the answer back into Roman numerals.

  1. Change DLXII into a number. Split it into groups and add.
    DLXII = D (500) + L (50) + X (10) + I (1) + I (1) = 562
  2. Change CXXXVIII into a number. Do the same.
    CXXXVIII = C (100) + X (10) + X (10) + X (10) + V (5) + I (1) + I (1) + I (1) = 138
  3. Do the calculation. Use our normal numbers.
    562 + 138 = 700
  4. Change the answer back to Roman numerals. Thousands, hundreds, tens, then ones.
    700 = DCC = DCC

Check. Read DCC again: 500 + 100 + 100 = 700. ✓

Watch out. Roman numerals are hard to add directly. Change them to numbers first.

Worked example 1.6.8
Write < or > between the Roman numerals:   CM  [ ? ]  DCCLXXXVIII

Method. Change both Roman numerals into numbers. Then compare the numbers.

  1. Change CM into a number. Split into groups and add.
    CM = 900
  2. Change DCCLXXXVIII into a number. Do the same.
    DCCLXXXVIII = 788
  3. Compare the numbers. Compare from the left, as usual.
    900 > 788
  4. Write the answer with the Roman numerals.
    CM > DCCLXXXVIII

Check. CM is 112 more than DCCLXXXVIII. ✓

Watch out. Do not compare the number of letters. A short numeral like CM (900) can be bigger than a long one like DCCLXXXVIII (788).

Worked example 1.6.9
The first Moon landing was in MCMLXIX. How many years before 2026 was that?

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Change the Roman numeral into a year in digits, then take it away from the later year.

  1. Change MCMLXIX into a year. Split it into groups and add.
    MCMLXIX = M (1000) + CM (1000 − 100) + L (50) + X (10) + IX (10 − 1) = 1969
  2. Decide which year is later. The later year is the bigger number. We take the earlier year away from it.
    1969 < 2026
  3. Subtract from the later year. 2026 is the later year.
    2026 − 1969 = 57

Check. 1969 + 57 = 2026. ✓

Watch out. Write the years as ordinary numbers before you subtract.

Watch out

Do not write 49 as IL or 99 as IC. I can only go before V or X, so 49 is XL + IX = XLIX and 99 is XC + IX = XCIX. And do not write 4 as IIII or 900 as DCCCC: they are IV and CM. Never put the same symbol more than three times in a row.

Exercise 1F  Roman numerals

Non-calculator
1
FWrite each Roman numeral as a number. The chart shows the symbols.
I1V5X10L50C100D500M1,000
(a)CLIX
(b)DXLIV
(c)CMXC
(d)DCCCLXXXVIII
(e)CDXLIX
(f)MCDLX
2
FWrite each number in Roman numerals.
(a)134
(b)478
(c)909
(d)640
(e)999
(f)1,000
3
FQuick-fire! Write each number in Roman numerals.
(a)400
(b)500
(c)900
(d)600
(e)90
(f)1,000
4
FEach Roman numeral is a year. Write each year in digits.
(a)MCMLXXXIV
(b)MDCLXVI
(c)MCCXV
(d)MMXXIV
5
FThe sign on a railway station says it was built in the year on the plaque. In which year was the station built? Write the year in digits.
MCMXIIRailway station
6
FWrite each year in Roman numerals.
(a)1066: The Battle of Hastings
(b)1666: The Great Fire of London
(c)1948: The NHS began
(d)2026: This year
7
FWrite < or > between each pair of Roman numerals.
(a)CDXL  [ ? ]  CCCXLIV
(b)DCCLXXXIX  [ ? ]  DCCXC
(c)CM  [ ? ]  DCCCXCIX
8
FWrite these Roman numerals in order, smallest first.   DCLXVI,  DCXLIX,  DLXVI,  DCC,  CMXC
9
FWork out each answer. Write the answer in Roman numerals, with the number in brackets.
(a)XC + CCX
(b)DL + CCCXV
(c)M − CDXL
(d)DCCC − CCLXV
(e)CMXC − DLX
10
PSA film was made in MCMXCIV. How many years before 2026 was it made?
11
PSOne Roman road is CCCLXXV kilometres long. Another is DXL kilometres long. How much longer is the second road? Write your answer as a number.
12
RTom writes 1,999 as MIM and 490 as XD. Both are wrong. Write the correct Roman numerals.
13
RThree of these Roman numerals are written incorrectly. Which three? Explain what is wrong with each.   XXXX   MCMXCIX   VX   XCIV   IL
14
RWhich year from 1000 to 2026 needs the most letters when it is written in Roman numerals? How many letters does it need?
1.7

Solving number and practical problems

Year 5
Solve number and practical problems, Use rounding, ordering, negative numbers and counting together

Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page

Video lesson: Solving number and practical problemsComing soon

Now you can put everything together. Problems about big numbers can use place value, ordering, counting in powers of 10, rounding, negative numbers and Roman numerals. Here is a plan that works for every problem.

  1. Read the problem twice. Underline the numbers and the question.
  2. Picture it. Draw a number line, a table, a chart or a bar model.
  3. Choose what to do: count on, compare, round, add or take away.
  4. Work it out one step at a time.
  5. Check: does the answer make sense? Use an estimate.
0100,000200,000300,000400,000Park A245,000Park B318,500Park C287,000Park D96,200
Visitors to four parks in one year. The bars have their exact values written on them.

Look at the bar chart. Always read the scale and the labels before you answer. The numbers on the bars are exact, so you can round them, compare them and find differences.

Key words. A clue is a fact that helps you find an unknown number. When a problem has several clues, use them one at a time and cross out the numbers that do not fit.

Key ideas

  • Plan: read, picture, choose, work out, check.
  • Round the real numbers, not numbers that have already been rounded.
  • With clues, start with the clue that gives the most information.
  • Use an estimate to check that an answer is sensible.
  • Say what your answer means (units, names, years).
Worked example 1.7.1
The bar chart shows the number of visitors to four parks. Which two parks have the same number of visitors when each number is rounded to the nearest 100,000?
0100,000200,000300,000400,000Park A245,000Park B318,500Park C287,000Park D96,200

Method. Round every number to the nearest 100,000. Then see which ones are the same.

  1. Round each number. Look at the ten thousands digit each time: 5 or more rounds up, 4 or less rounds down.
    Park A: 245,000 (digit 4) ≈ 200,000
    Park B: 318,500 (digit 1) ≈ 300,000
    Park C: 287,000 (digit 8) ≈ 300,000
    Park D: 96,200 (digit 9) ≈ 100,000
  2. Find the numbers that are the same.
    Park B and Park C both round to 300,000.
  3. Write the answer.
    Park B and Park C

Check. The other parks round to different numbers. ✓

Watch out. Round the real numbers, not the rounded ones, each time.

Worked example 1.7.2
Use all six cards to make the largest number that rounds to 600,000 when rounded to the nearest 100,000.
603851

Method. First find the range of numbers that round to 600,000. Then use the cards to make the largest number in that range.

  1. Find the range for 600,000. To the nearest 100,000, the numbers that round to 600,000 go from 550,000 to 649,999.
    550,000 to 649,999
  2. Choose the first digit. The number must be at most 649,999, so the first digit is 6.
    First digit = 6
  3. Choose the next digit. The number must still be at most 649,999, so the second digit has to be 4 or less. Take the biggest card that fits.
    Second digit = 3
  4. Put the other cards in order, biggest first. This makes the number as big as possible.
    638,510

Check. 638,510 is between 550,000 and 649,999 and uses every card once. ✓

Watch out. Check your answer rounds to the right number.

Worked example 1.7.3
Sam is thinking of a number.
Rounded to the nearest 100,000 it is 400,000.
Rounded to the nearest 10,000 it is 350,000.
The thousands digit is 4.
The tens digit and ones digit are the same. The hundreds digit is 2 more than the ones digit.
The digits add up to 26.
What is the number?

Method. Use the rounding clues first to find the range. Then use the digit clues.

  1. Use the clue about 10,000. To round to 350,000 the number is from 345,000 to 354,999.
    345,000 to 354,999
  2. Use the clue about 100,000. To round to 400,000 the number must be at least 350,000. Together with the first clue:
    350,000 to 354,999. So the number starts 35 and the thousands digit is 0 to 4.
  3. Use the thousands digit. The thousands digit is 4.
    354,…
  4. Use the last three digits. Let the ones digit be o. The tens digit is o and the hundreds digit is o + 2. The digits 3, 5, 4 add to 12, so 12 + (o + 2) + o + o = 26.
    14 + 3o = 26
    3o = 12, so o = 4
  5. Write the number. Ones 4, tens 4, hundreds 6.
    354,644

Check. 354,644 ≈ 350,000 (10,000) ✓, ≈ 400,000 (100,000) ✓, thousands 4 ✓, 4 = 4 and 6 = 4 + 2 ✓, 3+5+4+6+4+4 = 26 ✓

Watch out. Check your answer against every clue.

Worked example 1.7.4
A charity has £235,000. It raises £10,000 more each month. It needs at least £300,000. After how many months will it have enough?

Method. Add 10,000 each month until the total is 300,000 or more.

  1. Start with the money now. Month 0.
    Month 0: £235,000
  2. Add £10,000 each month. Only the ten thousands digit changes.
    Month 1: £245,000
    Month 2: £255,000
    Month 3: £265,000
    Month 4: £275,000
    Month 5: £285,000
    Month 6: £295,000
    Month 7: £305,000
  3. Find the first total of 300,000 or more. Month 6 is £295,000, which is not enough. Month 7 is £305,000.
    7 months

Check. 235,000 + 7 × 10,000 = 305,000, which is at least 300,000. ✓

Watch out. £295,000 is close, but it is less than £300,000, so it is not enough.

Worked example 1.7.5
A diver is at −24 m. She swims up 9 m and then dives down 15 m. How far below sea level is she now?

Method. Do the moves one at a time. Going up adds. Going down takes away.

  1. Start position. Below sea level is negative.
    −24 m
  2. Swim up 9 m. Going up makes the number bigger.
    −24 m up 9 m: start below zero and go up 9 m → −15 m
  3. Dive down 15 m. Going down makes the number smaller.
    −15 m down 15 m: start at or below zero and go down 15 m more → −30 m
  4. Write the answer. The question asks how far below sea level, so give the depth.
    She is at −30 m, which is 30 m below sea level.

Check. Total change = +9 − 15 = −6. −24 − 6 = −30. ✓

Watch out. Take the moves in order and watch which way each one goes.

Worked example 1.7.6
A church was built in the year MDCCLXXXIX. Write the year in digits and round it to the nearest 100.

Key words. Roman numerals are letters used for numbers: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000. A small symbol before a bigger one is taken away; after it is added.

Method. Change the Roman numeral to a year, then round it.

  1. Change MDCCLXXXIX to a number. M = 1,000, D = 500, CC = 200, LXXX = 80, IX = 9.
    1,000 + 500 + 200 + 80 + 9 = 1789
  2. Look at the tens digit. Rounding to the nearest 100 means looking at the tens digit.
    1789: tens digit is 8, which is 5 or more, so round up
  3. Round. The hundreds go up by 1.
    1789 ≈ 1800

Check. 1,789 is 11 away from 1,800 and 89 away from 1,700. 1,800 is nearer. ✓

Watch out. Write the year in digits first, then round.

Worked example 1.7.7
Write < or > in the box:   sixty-two thousand and four  [ ? ]  62,040

Key words. < means “less than” and > means “greater than”. The wide end of the sign faces the bigger number.

Method. Compare the digits from the left, one column at a time. The first column that is different tells you which number is bigger.

  1. Write each side as one number. We can only compare numbers when they are written the usual way.
    sixty-two thousand and four = 62,004
    62,040 = 62,040
  2. Write both numbers in a place-value table. Lining up the columns lets us compare digit by digit.
    ThousandsOnes
    TThThHTO
    62,00462004
    62,04062040
  3. Compare the digits from the left. The first column where they are different decides which number is bigger.
    ten thousands: 6 and 6 are the same, so look at the next column.
    thousands: 2 and 2 are the same, so look at the next column.
    hundreds: 0 and 0 are the same, so look at the next column.
    tens: 0 and 4 are different. 0 < 4, so 62,004 is smaller.
  4. Write the correct symbol. < means “is less than”, > means “is greater than”, = means “is equal to”.
    62,004 < 62,040

Check. Picture a number line: 62,004 is to the left of 62,040. ✓

Watch out. Start at the LEFT (the biggest column). Do not start with the ones.

Watch out

Do not stop when you have a number. Check that it answers the question (for example “how many months” or “how far below sea level”), and check it against every clue. Remember to round the real numbers, never numbers that are already rounded.

Exercise 1G  Problems and puzzles

Non-calculator
1
PSThe bar chart shows the number of visitors to four parks in one year.
0100,000200,000300,000400,000Park A245,000Park B318,500Park C287,000Park D96,200
(a)Which park had the most visitors?
(b)Round the number of visitors to Park D to the nearest 10,000.
(c)Which two parks have the same number of visitors when rounded to the nearest 100,000?
2
PSUse all six cards to make the largest number that rounds to 500,000 when rounded to the nearest 100,000.
504928
3
RI am a six-digit number.
Rounded to the nearest 100,000 I am 800,000.
Rounded to the nearest 10,000 I am 840,000.
Rounded to the nearest 1,000 I am 838,000.
My hundreds digit is 4.
My tens digit is double my ones digit, and my ones digit is not 0.
My digits add up to 35.
What number am I?
4
PSA football stadium has 62,500 seats. Each year for 5 years it adds 1,000 more seats. Then 10,000 seats are taken out to make room for a new stand.
(a)How many seats are there after 5 years of adding seats?
(b)How many seats are there after the stand is built?
5
PSA diver is at −24 m. She swims up 9 m and then dives down 15 m.
(a)Where is she now?
(b)Another diver is at −11 m. How much deeper is the first diver than the second?
6
PSA theatre sells 4,980 tickets in the first week and 5,120 tickets in the second week. Estimate the total number of tickets sold by rounding each number to the nearest 1,000.
7
PSA church was built in the year MDCCLXXXIX. Round that year to the nearest 100.
8
ROne newspaper says that 80,000 people watched a match (to the nearest 10,000). Another newspaper says that 84,000 people watched (to the nearest 1,000). Could both newspapers be correct? Explain.
9
RWhich one is different?   1,000 + 200 + 5    1,250    MCCV    one thousand, two hundred and five
10
RIs this always, sometimes or never true?
“When you round a number to the nearest 100, the answer is bigger than the number.”
11
RWhat is the largest whole number that rounds to 500,000 when rounded to the nearest 100,000, and has six different digits?

Chapter summary

SkillMethod
Read and write large numbersSplit into periods with commas: Millions | Thousands | Ones. Zeros are place holders. 999,999 + 1 = 1,000,000.
Value of a digitDigit × value of its column. The 4 in 340,000 is worth 40,000. Partition: 306,075 = 300,000 + 6,000 + 70 + 5.
Compare and orderMore digits means bigger. Same digits: compare from the left. < less than, > greater than.
Counting in powers of 10Only one digit changes (the column that matches the step). Carry for a 9 going up, swap for a 0 going down.
Missing termsFind two known numbers, divide the difference by the number of jumps, then fill the gaps.
Negative numbersBelow zero. Further left is smaller. Split jumps that cross zero. Difference across zero: add the distances.
RoundingLook at the digit to the right. 5 or more: round up. 4 or less: round down. Halfway rounds up.
EstimatingRound each number, then calculate. Use the estimate to check an answer.
Roman numeralsI 1, V 5, X 10, L 50, C 100, D 500, M 1,000. Thousands, hundreds, tens, ones. MCMXCIX = 1,999, MMXXVI = 2,026.

Can you…?

  • I can read, write and partition numbers up to 1,000,000.
  • I can say the value of any digit.
  • I can order and compare numbers up to 1,000,000.
  • I can count on and back in 10s, 100s, 1,000s, 10,000s and 100,000s, and fill missing numbers.
  • I can use negative numbers for temperatures, depths and bank balances and count through zero.
  • I can round to the nearest 10, 100, 1,000, 10,000 and 100,000.
  • I can use rounding to estimate and to check answers.
  • I can read Roman numerals up to 1,000 and years such as MMXXVI.
  • I can solve problems and puzzles that use all of these ideas.

Key terms

Period
A group of three columns in a big number: Ones, Thousands, Millions.
Digit
One of the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
Place value
The value of a digit depends on its column.
Place holder
A zero that holds an empty column so the other digits stay in the right place.
Partition
To split a number into the value of each digit: 4,306 = 4,000 + 300 + 6.
Ascending
Getting bigger: smallest first.
Descending
Getting smaller: biggest first.
Power of 10
The numbers 10, 100, 1,000, 10,000, 100,000 and so on. Each is 10 times the one before.
Sequence
A list of numbers that follow a rule.
Negative number
A number less than zero, written with a minus sign, like −5.
Overdrawn
A bank balance below zero. You owe the bank money.
Round
To change a number to a nearby, simpler number, such as to the nearest 1,000.
Estimate
A sensible answer that is close to the exact one.
Roman numerals
Letters used for numbers by the Romans: I, V, X, L, C, D, M.

Exercise 1Z  Check-up (non-calculator)

Non-calculator
1
What is the value of the underlined digit in 245,310?
2
Write 305,080 in words.
3
What is 10,000 less than 215,000?
4
Write these numbers in order, smallest first.   472,510,  427,510,  472,150,  47,251
5
Count back in 10,000s from 305,000. Write the next three numbers.
6
Round 683,472 to the nearest 10,000.
7
The temperature is 3°C. It falls by 8°C. What is the new temperature?
8
Write in order, smallest first:   −6,   2,   −1,   −10
9
Write 474 in Roman numerals.
10
A film was made in the year MCMLXXXVIII. Write the year in digits.

Total 17 marks. Allow about 17 minutes.

Exercise 1X  SATs-style questions

Non-calculator
1
FWrite the number that is 10,000 more than 396,500.[1 mark]
2
FWhich number has 6 in the thousands column?   Tick one box.   24,600   60,450   604,500   546,000[1 mark]
3
FWrite two hundred and six thousand and forty in digits.[1 mark]
4
FRound 74,950 to the nearest 100.[1 mark]
5
FWrite the missing numbers in the sequence.
346,200,  347,200,  ?,  ?,  350,200
[2 marks]
6
PSAt 6 a.m. the temperature was −7°C. By noon it had risen by 12°C. What was the temperature at noon?[2 marks]
7
FWrite these numbers in order, smallest first.   530,800,  508,300,  538,000,  503,800[2 marks]
8
PSOne TV programme ends with the year MCMXCVIII. Another ends with the year MMXXV. How many years are between them? Write your answer as a number.[2 marks]
9
RAmira says, “98,000 rounded to the nearest 100,000 is 90,000.” Is Amira correct? Explain how you know.[2 marks]
10
RSam thinks of a six-digit number.
Rounded to the nearest 100,000 it is 500,000.
Rounded to the nearest 10,000 it is 450,000.
What is the smallest number Sam could be thinking of? What is the largest? Show how you know.
[3 marks]

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