Year 1 Numbers to 100: check-up and quiz

Key words. To count on is to say the next numbers in order, one more each time.

Method. Start at 65. Say the next number each time, one at a time.

1. Start at 65. Put your finger on the number you start from.
   Start: 65
2. Say 3 numbers, one at a time. Each new number is one more than the one before.
   66, 67, 68
3. Write the numbers in order. Write each number you said.
   66, 67, 68

Check. Count back from 68 to 65 with your finger. The same numbers come again. ✓

Watch out. Do not say 65 again. Start with the number after it.

Method. Count back in tens from 80.

1. Start at 80. Put your finger on the starting number.
   Start: 80
2. Take away 10 each time. Change the tens. The ones stay at 0.
   70, 60, 50
3. Write the next 3 numbers.
   70, 60, 50

Check. 80 − 10 = 70. ✓

Watch out. Do not write the starting number again. Start with the next one.

Key words. A ten is a bundle of ten ones. A one is a single thing.

Method. Count the groups of ten first. Then count the ones left over.

1. Count the tens in 84. Each group of ten is one ten.
   80 is 8 tens
2. Count the ones left over. The ones are what is left after the tens.
   84 − 80 = 4 ones
3. Write the answer.
   8 tens and 4 ones

Check. Put them back together: 80 + 4 = 84. ✓

Watch out. The tens come first when you say the number. 25 is 2 tens and 5 ones, not 5 tens and 2 ones.

Method. Start with the tens, then add the ones.

1. Write 7 tens. The tens go on the left.
   7 tens = 70
2. Add 3 ones. The ones go on the right, after the tens.
   70 + 3 = 73
3. Write the number.
   73

Check. Read it back: 73 has 7 tens and 3 ones. ✓

Watch out. The tens digit goes on the left. Write 7 tens and 3 ones as 73, not 37.

Key words. After means one more. Before means one less.

Method. After means one more. Find 48 on the 100 square first.

1. Find 48 on the 100 square. 48 is 4 tens and 8 ones.
   48 = 4 tens and 8 ones
2. Move one step on. After means one more. Move one step on.
   48 + 1 = 49
3. Write the answer.
   49

Check. Count on one from 48 and you say 49. ✓

Watch out. Do not write 48 again. The answer is the next number.

Key words. After means one more. Before means one less.

Method. Before means one less. Find 91 on the 100 square first.

1. Find 91 on the 100 square. 91 is 9 tens and 1 one.
   91 = 9 tens and 1 one
2. Move one step back. Before means one less. Move one step back.
   91 − 1 = 90
3. Write the answer.
   90

Check. Count back one from 91 and you say 90. ✓

Watch out. Do not write 91 again. The answer is the number just before.

Method. 10 more means one row down on the 100 square. Only the tens change.

1. Find 52. 52 is 5 tens and 2 ones.
   52 = 5 tens and 2 ones
2. Change the tens. Add one ten. The ones stay the same.
   6 tens and 2 ones
3. Write the answer.
   62

Check. 52 + 10 = 62. ✓

Watch out. Only the tens change. 52 becomes 62, not 53.

Key words. Bigger means more. Smaller means less.

Method. Compare the tens first. Only compare the ones if the tens are the same.

1. Look at the tens of each number. The tens tell us the big part of the number.
   74: 7 tens   47: 4 tens
2. Compare the tens. The number with more tens is the bigger number.
   7 tens is more than 4 tens
3. Write the answer. Bigger means more.
   74

Check. On the 100 square, 74 is further along than 47. ✓

Watch out. A number with more ones is not always bigger. Compare the tens first.

Key words. Smallest is the least. Biggest is the most.

Method. Compare the tens first, then the ones, and put the numbers in order.

1. Look at the tens of each number. A number with fewer tens is smaller.
   58: 5 tens   49: 4 tens   81: 8 tens   15: 1 tens
2. Put them in order, smallest first. Start with the smallest number, then the next one.
   15, 49, 58, 81
3. Write the answer.
   15, 49, 58, 81

Check. There are 4 numbers in the question and 4 in the answer. ✓

Watch out. Check you have not left a number out, and that each number is used once.

Method. Use the numbers above and below each empty box. Going down one row adds 10.

1. Look above and below each empty box. The number above is 10 less. The number below is 10 more.
   77: 67 above, 87 below
2. Work out each missing number. The empty box is 10 more than the number above it.
   67 + 10 = 77
3. Write the missing numbers.
   77

Check. Check it: the number below each box is 10 more than the box. ✓

Watch out. Look up or down the column. Do not guess from the numbers next to the box.

Key words. After means one more. Before means one less.

Method. After means one more. Find 79 on the 100 square first.

1. Find 79 on the 100 square. 79 is 7 tens and 9 ones.
   79 = 7 tens and 9 ones
2. Move one step on. This number is at the end of a row. The next number starts the next row.
   79 + 1 = 80
3. Write the answer.
   80

Check. Count on one from 79 and you say 80. ✓

Watch out. Do not write 79 again. The answer is the next number.

Method. Start with the tens, then add the ones.

1. Write 5 tens. The tens go on the left.
   5 tens = 50
2. Add 6 ones. The ones go on the right, after the tens.
   50 + 6 = 56
3. Write the number.
   56

Check. Read it back: 56 has 5 tens and 6 ones. ✓

Watch out. The tens digit goes on the left. Write 5 tens and 6 ones as 56, not 65.

Key words. A ten is a bundle of ten ones. A one is a single thing.

Method. Count the groups of ten first. Then count the ones left over.

1. Count the tens in 38. Each group of ten is one ten.
   30 is 3 tens
2. Count the ones left over. The ones are what is left after the tens.
   38 − 30 = 8 ones
3. Write the answer.
   3 tens and 8 ones

Check. Put them back together: 30 + 8 = 38. ✓

Watch out. The tens come first when you say the number. 25 is 2 tens and 5 ones, not 5 tens and 2 ones.

Method. Each number is 10 more than the one before it.

1. Look at the numbers around each gap. The numbers go up or down by the same amount each time.
   20, 30, ?, 50
2. Work out each missing number. Use the number before the gap, and add 10.
   Gap 3: 30 + 10 = 40
3. Write the missing numbers.
   40

Check. Read the whole line again. Every number is 10 more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go on by the same amount.

Method. 10 less means one row up on the 100 square. Only the tens change.

1. Find 64. 64 is 6 tens and 4 ones.
   64 = 6 tens and 4 ones
2. Change the tens. Take away one ten. The ones stay the same.
   5 tens and 4 ones
3. Write the answer.
   54

Check. 64 − 10 = 54. ✓

Watch out. Only the tens change. 64 becomes 54, not 63.

Key words. Bigger means more. Smaller means less.

Method. Compare the tens first. Only compare the ones if the tens are the same.

1. Look at the tens of each number. The tens tell us the big part of the number.
   61: 6 tens   16: 1 tens
2. Compare the tens. The number with more tens is the bigger number.
   6 tens is more than 1 tens
3. Write the answer. Bigger means more.
   61

Check. On the 100 square, 61 is further along than 16. ✓

Watch out. A number with more ones is not always bigger. Compare the tens first.

Key words. To count back is to say the numbers before, one less each time.

Method. Start at 40. Say the number before it, then the one before that.

1. Start at 40. Put your finger on the number you start from.
   Start: 40
2. Say 5 numbers, going back. Each number is one less than the one before.
   39, 38, 37, 36, 35
3. Write the numbers in order. Write each number you said.
   39, 38, 37, 36, 35

Check. Count on from 35 to 40 to check. The same numbers come again. ✓

Watch out. Do not say 40 again. Start with the number just before it.

Method. Each number is 1 more than the one before it.

1. Look at the numbers around each gap. The numbers go up or down by the same amount each time.
   96, 97, ?, 99, 100
2. Work out each missing number. Use the number before the gap, and add 1.
   Gap 3: 97 + 1 = 98
3. Write the missing numbers.
   98

Check. Read the whole line again. Every number is 1 more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go on by the same amount.

Key words. A ten is a bundle of ten ones. A one is a single thing.

Method. Count the groups of ten first. Then count the ones left over.

1. Count the tens in 60. Each group of ten is one ten.
   60 is 6 tens
2. Count the ones left over. The ones are what is left after the tens.
   60 − 60 = 0 ones
3. Write the answer.
   6 tens and 0 ones

Check. Put them back together: 60 + 0 = 60. ✓

Watch out. The tens come first when you say the number. 25 is 2 tens and 5 ones, not 5 tens and 2 ones.

Key words. Bigger means more. Smaller means less.

Method. Compare the tens first. Only compare the ones if the tens are the same.

1. Look at the tens of each number. The tens tell us the big part of the number.
   Leo: 3 tens   Aisha: 2 tens
2. Compare the tens. The number with more tens is the bigger number.
   3 tens is more than 2 tens
3. Write the answer. Bigger means more.
   Leo

Check. On the 100 square, 30 is further along than 25. ✓

Watch out. A number with more ones is not always bigger. Compare the tens first.