Year 1: Counting to 20

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
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 11.
3. Write the answer.
   There are 11 balls.

Check. Count again from the other side. You get 11 again. ✓

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

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, 16
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 16.
3. Write the answer.
   There are 16 stars.

Check. Count again from the other side. You get 16 again. ✓

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

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
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 13.
3. Write the answer.
   There are 13 cubes.

Check. Count again from the other side. You get 13 again. ✓

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

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, 16, 17, 18, 19, 20
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 20.
3. Write the answer.
   There are 20 apples.

Check. Count again from the other side. You get 20 again. ✓

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

Method. Start at 12. Count on one number at a time until you reach 16.

1. Start at 12. That is the first number you say.
   12
2. Count on one at a time to 16. Each number is one more than the number before it.
   12, 13, 14, 15, 16
3. Write the numbers. Include the first number and the last number.
   12, 13, 14, 15, 16

Check. Count back from 16 to 12 to check. ✓

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

Method. Count back from 18 to 14. Each number is one less than the number before it.

1. Start at the first number. We start with the biggest number.
   18
2. Take away one each time. Each number is one less than the one before.
   18, 17, 16, 15, 14
3. Write the numbers. Include the start number and the end number.
   18, 17, 16, 15, 14

Check. Count on from 14 to 18 to check. ✓

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

Method. Start at 18. Count on one number at a time until you reach 22.

1. Start at 18. That is the first number you say.
   18
2. Count on one at a time to 22. Each number is one more than the number before it.
   18, 19, 20, 21, 22
3. Write the numbers. Include the first number and the last number.
   18, 19, 20, 21, 22

Check. Count back from 22 to 18 to check. ✓

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

Method. Start at 10. Count on one number at a time until you reach 20.

1. Start at 10. That is the first number you say.
   10
2. Count on one at a time to 20. Each number is one more than the number before it.
   10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
3. Write the numbers. Include the first number and the last number.
   10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20

Check. Count back from 20 to 10 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, 16, ?, 18
2. Count on one from the number before each gap. Add 1 to the number before the gap.
   Gap 3: 16 + 1 = 17
3. Write the missing numbers.
   17

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 back from 14 to 11. Each number is one less than the number before it.

1. Start at the first number. We start with the biggest number.
   14
2. Take away one each time. Each number is one less than the one before.
   14, 13, 12, 11
3. Write the numbers. Include the start number and the end number.
   14, 13, 12, 11

Check. Count on from 11 to 14 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. 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, 16, 17, 18, 19
2. Look at the last number you said. The last number tells us how many there are altogether.
   The last number is 19.
3. Write the answer.
   There are 19 stars.

Check. Count again from the other side. You get 19 again. ✓

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

Method. Count forwards from 9, then backwards from 12. Check each number is one more or one less than the one next to it.

1. Count forwards from 9 to 12. Each number is one more than the one before.
   9, 10, 11, 12
2. Count backwards from 12 to 9. Each number is one less than the one before.
   12, 11, 10, 9
3. Check both ways. The same numbers appear in both lists, in opposite orders.
   Yes. Both ways are right.

Check. Count forwards and backwards along the same numbers. ✓

Watch out. Going up adds one each time. Going down takes one away each time.