Year 2: Counting in twos, threes and fives

Method. Start at 0. Count on in twos.

1. Start at 0. Put your finger on the number you start from.
   Start: 0
2. Say each number, going on 2 each time. Each new number is 2 more than the one before.
   2, 4, 6
3. Write the numbers in order. Write each number you said.
   2, 4, 6

Check. Count back from 6. You reach 0. ✓

Watch out. Do not say 0 again. Start with the next number.

Method. The numbers go up by 2 each time.

1. Look at the numbers around each gap. Each number is 2 more than the one before it.
   8, 10, ?, 14
2. Work out each missing number. Add 2 to the number before the gap.
   10 + 2 = 12
3. Write the missing numbers.
   12

Check. Count on in 2s through the whole line. It works. ✓

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

Method. Start at 0. Count on in threes.

1. Start at 0. Put your finger on the number you start from.
   Start: 0
2. Say each number, going on 3 each time. Each new number is 3 more than the one before.
   3, 6, 9
3. Write the numbers in order. Write each number you said.
   3, 6, 9

Check. Count back from 9. You reach 0. ✓

Watch out. Do not say 0 again. Start with the next number.

Method. The numbers go up by 3 each time.

1. Look at the numbers around each gap. Each number is 3 more than the one before it.
   12, ?, 18, 21, ?
2. Work out each missing number. Add 3 to the number before the gap.
   12 + 3 = 15
   21 + 3 = 24
3. Write the missing numbers.
   15, 24

Check. Count on in 3s through the whole line. It works. ✓

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

Method. Start at 0. Count on in fives.

1. Start at 0. Put your finger on the number you start from.
   Start: 0
2. Say each number, going on 5 each time. Each new number is 5 more than the one before.
   5, 10, 15, 20
3. Write the numbers in order. Write each number you said.
   5, 10, 15, 20

Check. Count back from 20. You reach 0. ✓

Watch out. Do not say 0 again. Start with the next number.

Method. The numbers go up by 5 each time.

1. Look at the numbers around each gap. Each number is 5 more than the one before it.
   25, ?, 35, ?, 45
2. Work out each missing number. Add 5 to the number before the gap.
   25 + 5 = 30
   35 + 5 = 40
3. Write the missing numbers.
   30, 40

Check. Count on in 5s through the whole line. It works. ✓

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

Method. Start at 10. Count on in twos.

1. Start at 10. Put your finger on the number you start from.
   Start: 10
2. Say each number, going on 2 each time. Each new number is 2 more than the one before.
   12, 14, 16, 18
3. Write the numbers in order. Write each number you said.
   12, 14, 16, 18

Check. Count back from 18. You reach 10. ✓

Watch out. Do not say 10 again. Start with the next number.

Method. Start at 20. Count back in twos.

1. Start at 20. Put your finger on the number you start from.
   Start: 20
2. Say each number, going back 2 each time. Each new number is 2 less than the one before.
   18, 16, 14, 12
3. Write the numbers in order. Write each number you said.
   18, 16, 14, 12

Check. Count on from 12. You reach 20. ✓

Watch out. Do not say 20 again. Start with the next number.

Method. Start at 30. Count back in threes.

1. Start at 30. Put your finger on the number you start from.
   Start: 30
2. Say each number, going back 3 each time. Each new number is 3 less than the one before.
   27, 24, 21
3. Write the numbers in order. Write each number you said.
   27, 24, 21

Check. Count on from 21. You reach 30. ✓

Watch out. Do not say 30 again. Start with the next number.

Method. Start at 50. Count back in fives.

1. Start at 50. Put your finger on the number you start from.
   Start: 50
2. Say each number, going back 5 each time. Each new number is 5 less than the one before.
   45, 40, 35
3. Write the numbers in order. Write each number you said.
   45, 40, 35

Check. Count on from 35. You reach 50. ✓

Watch out. Do not say 50 again. Start with the next number.

Method. There are 4 groups of 2. Count in 2s to find the total.

1. Count the groups: 4. Each group has 2 socks.
   4 groups of 2
2. Count in 2s, one group at a time. Add 2 for every group.
   2, 4, 6, 8
3. Write the total.
   8

Check. Count in 2s to check. The last number you say is 8. ✓

Watch out. Count in 2s, not in ones. Each group is 2.

Method. There are 3 groups of 5. Count in 5s to find the total.

1. Count the groups: 3. Each group has 5 marbles.
   3 groups of 5
2. Count in 5s, one group at a time. Add 5 for every group.
   5, 10, 15
3. Write the total.
   15

Check. Count in 5s to check. The last number you say is 15. ✓

Watch out. Count in 5s, not in ones. Each group is 5.

Method. Count in threes from 0 and check whether 6 is said.

1. Count in threes from 0. Say each number, one step at a time.
   3, 6, 9, 12
2. Look for 6 in the list. Six is the second number we say.
   6 is in the list
3. Write the answer. Two threes make six: 3 + 3 = 6.
   Yes

Check. Count on from 3: 3, then 3 more is 6. ✓

Watch out. Look at the steps, not just the start. 6 is two steps of 3.