Year 1 Numbers to 20: check-up and quiz

Key words. To count is to say one number for each thing, in order: 1, 2, 3, and so on.

Method. Say one number for each one, and touch each one only once. The last number you say is how many there are.

1. Count each one and say its number. Each one gets one number. Do not miss one and do not count one twice.
   1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 15.
3. Write the answer.
   There are 15 apples.

Check. Count again from the other side. You get 15 again. ✓

Watch out. Move each one to one side as you count it, so you do not lose your place.

Method. Read the number word, then find it on the number list.

1. Read the word. Read the whole word, not just the first letters.
   “thirteen”
2. Find the word on the number list. Each word matches exactly one number.
   thirteen = 13
3. Write the numeral. A numeral is the number written with digits.
   13

Check. Count 13 things. The last number you say is 13. ✓

Watch out. Teen numbers end in teen. Check every letter of thirteen.

Key words. A numeral is a number written with digits, like 14. A number word is its name, like fourteen.

Method. Say the number out loud, then write its name in words.

1. Say the number. Listen to how it sounds.
   18
2. Find its name on the number list. Every number has one name.
   18 = eighteen
3. Write the word, one letter at a time. The word has 8 letters.
   eighteen

Check. Count out 18 things and say “eighteen” at the end. ✓

Watch out. Teen numbers end in teen. Check every letter of eighteen.

Key words. One more is the next number. One less is the number just before.

Method. Start at 12. One more is the number after 12.

1. Start at 12. Put your finger on the number.
   Start: 12
2. Move one step forward. Each step on the number line is one number.
   12 + 1 = 13
3. Write the answer.
   13

Check. Check it: 13 − 1 = 12. ✓

Watch out. Move one step, not two. Do not write the number you started with.

Key words. One more is the next number. One less is the number just before.

Method. Start at 16. One less is the number before 16.

1. Start at 16. Put your finger on the number.
   Start: 16
2. Move one step back. Each step on the number line is one number.
   16 − 1 = 15
3. Write the answer.
   15

Check. Check it: 15 + 1 = 16. ✓

Watch out. Move one step, not two. Do not write the number you started with.

Key words. More means a bigger number. Fewer means a smaller number. The same means equal.

Method. Count each group, then see which number is bigger.

1. Count group A. Touch each one once.
   Group A: 12 stars
2. Count group B. Touch each one once.
   Group B: 17 apples
3. Compare the two numbers. The bigger number has more. The smaller number has fewer.
   12 < 17
4. Write the answer.
   Group B has more apples.

Check. Match one to one: each thing in one group gets a partner from the other. The group with a thing left over has more. ✓

Watch out. Groups can look bigger when the things are spread out. Always count them.

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

Method. Smallest first. Look at where each number sits on the number line.

1. Find each number on the number line. Numbers further to the left are smaller.
2. Put the numbers in order. Start with the smallest and go to the next one.
   8, 11, 14, 19
3. Write the numbers.
   8, 11, 14, 19

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

Watch out. Check you have not left a number out.

Key words. Between means in the middle of two numbers.

Method. The number between 15 and 17 sits in the middle of them.

1. Find 15 and 17 on the number line. Put your finger on each one.
2. Count on one from the smaller number. The number in the middle is one more than the smaller one.
   15 + 1 = 16
3. Write the answer.
   16

Check. Count on from 16 to 17: 16 + 1 = 17. ✓

Watch out. The number between is not one of the two numbers you started with.

Method. Count the full tens first. Then count the ones that are left.

1. Count the tens. A ten is ten counters, or one full ten frame.
   1 ten = 10
2. Count the ones. The ones are the counters that are left over.
   7 ones
3. Write it with tens and ones. Say the tens first, then the ones.
   1 ten and 7 ones

Check. 10 + 7 = 17, so 17 is 1 ten and 7 ones. ✓

Watch out. Say the tens first, then the ones. One ten is 10, not 1.

Method. Count back from 20 to 17. Each number is one less than the number before it.

1. Start at the first number. We start with the biggest number.
   20
2. Take away one each time. Each number is one less than the one before.
   20, 19, 18, 17
3. Write the numbers. Include the start number and the end number.
   20, 19, 18, 17

Check. Count on from 17 to 20 to check. ✓

Watch out. Count back in the same way each time. Do not skip a number, and do not say a number twice.

Key words. One more is the next number. One less is the number just before.

Method. Start at 19. One more is the number after 19.

1. Start at 19. Put your finger on the number.
   Start: 19
2. Move one step forward. Each step on the number line is one number.
   19 + 1 = 20
3. Write the answer.
   20

Check. Check it: 20 − 1 = 19. ✓

Watch out. Move one step, not two. Do not write the number you started with.

Method. Read the number word, then find it on the number list.

1. Read the word. Read the whole word, not just the first letters.
   “twelve”
2. Find the word on the number list. Each word matches exactly one number.
   twelve = 12
3. Write the numeral. A numeral is the number written with digits.
   12

Check. Count 12 things. The last number you say is 12. ✓

Watch out. twelve does not end in teen. Learn it as its own name.

Key words. To count is to say one number for each thing, in order: 1, 2, 3, and so on.

Method. Say one number for each one, and touch each one only once. The last number you say is how many there are.

1. Count each one and say its number. Each one gets one number. Do not miss one and do not count one twice.
   1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 14.
3. Write the answer.
   There are 14 stars.

Check. Count again from the other side. You get 14 again. ✓

Watch out. Move each one to one side as you count it, so you do not lose your place.

Method. Start with the tens. Then add the ones.

1. Start with the tens. One ten is 10 counters.
   1 ten = 10
2. Add the ones. Count the ones on after the tens.
   10 + 6 = 16
3. Write the answer.
   16

Check. 1 ten and 6 ones is 16. ✓

Watch out. Do not write the tens and the ones next to each other. Add them to make one number.

Key words. More means a bigger number. Fewer means a smaller number. The same means equal.

Method. Count each group, then see which number is smaller.

1. Count group A. Touch each one once.
   Group A: 18 balls
2. Count group B. Touch each one once.
   Group B: 13 cubes
3. Compare the two numbers. The bigger number has more. The smaller number has fewer.
   18 > 13
4. Write the answer.
   Group B has fewer cubes.

Check. Match one to one: each thing in one group gets a partner from the other. The group with a thing left over has more. ✓

Watch out. Groups can look bigger when the things are spread out. Always count them.

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

Method. Smallest first. Look at where each number sits on the number line.

1. Find each number on the number line. Numbers further to the left are smaller.
2. Put the numbers in order. Start with the smallest and go to the next one.
   4, 9, 16, 20
3. Write the numbers.
   4, 9, 16, 20

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

Watch out. Check you have not left a number out.

Method. Start at 17. Count on one number at a time until you reach 20.

1. Start at 17. That is the first number you say.
   17
2. Count on one at a time to 20. Each number is one more than the number before it.
   17, 18, 19, 20
3. Write the numbers. Include the first number and the last number.
   17, 18, 19, 20

Check. Count back from 20 to 17 to check. ✓

Watch out. Do not skip a number when you go past ten. After nine comes ten, then eleven.

Method. Each number is one more than the number before it. Use the numbers you can see to find the gaps.

1. Look at the numbers before each gap. Counting on in ones means each number is one more than the one before.
   15, ?, 17, ?, 19
2. Count on one from the number before each gap. Add 1 to the number before the gap.
   Gap 2: 15 + 1 = 16
   Gap 4: 17 + 1 = 18
3. Write the missing numbers.
   16, 18

Check. Read the whole line again: each number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Count the full tens first. Then count the ones that are left.

1. Count the tens. A ten is ten counters, or one full ten frame.
   1 ten = 10
2. Count the ones. The ones are the counters that are left over.
   6 ones
3. Write it with tens and ones. Say the tens first, then the ones.
   1 ten and 6 ones

Check. 10 + 6 = 16, so 16 is 1 ten and 6 ones. ✓

Watch out. Say the tens first, then the ones. One ten is 10, not 1.

Method. Check Aisha’s idea by counting on from 19.

1. Count on from 19. One more than 19 is the next number.
   19, 20
2. Look at what Aisha said. Aisha said 20 comes before 19. But 19 comes before 20.
   19 comes before 20
3. Write the answer.
   No. 19 comes before 20, so 20 comes after 19.

Check. On the number line, 20 is one step right of 19. ✓

Watch out. The number that comes after is the bigger number.