Reception Maths: Finding the missing number

Method. Start at 7. Count back until you reach 4. The number of steps is the missing number.

1. Start at 7. That is the number we start with.
   7
2. Count back to 4. Count each step as you go down.
   6, 5, 4
3. Count the steps. The number of steps is the missing number.
   3 steps
4. Write the answer.
   3

Check. Check: 4 + 3 = 7. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 5. Count back until you reach 2. The number of steps is the missing number.

1. Start at 5. That is the number we start with.
   5
2. Count back to 2. Count each step as you go down.
   4, 3, 2
3. Count the steps. The number of steps is the missing number.
   3 steps
4. Write the answer.
   3

Check. Check: 2 + 3 = 5. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 9. Count back until you reach 5. The number of steps is the missing number.

1. Start at 9. That is the number we start with.
   9
2. Count back to 5. Count each step as you go down.
   8, 7, 6, 5
3. Count the steps. The number of steps is the missing number.
   4 steps
4. Write the answer.
   4

Check. Check: 5 + 4 = 9. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 6. Count back until you reach 6. The number of steps is the missing number.

1. Start at 6. That is the number we start with.
   6
2. Count back to 6. Count each step as you go down.
   no steps
3. Count the steps. The number of steps is the missing number.
   0 steps
4. Write the answer.
   0

Check. Check: 6 + 0 = 6. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 10. Count back until you reach 7. The number of steps is the missing number.

1. Start at 10. That is the number we start with.
   10
2. Count back to 7. Count each step as you go down.
   9, 8, 7
3. Count the steps. The number of steps is the missing number.
   3 steps
4. Write the answer.
   3

Check. Check: 7 + 3 = 10. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 8. Count back until you reach 1. The number of steps is the missing number.

1. Start at 8. That is the number we start with.
   8
2. Count back to 1. Count each step as you go down.
   7, 6, 5, 4, 3, 2, 1
3. Count the steps. The number of steps is the missing number.
   7 steps
4. Write the answer.
   7

Check. Check: 1 + 7 = 8. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 8. Count back until you reach 3. The number of steps is the missing number.

1. Start at 8. That is the number we start with.
   8
2. Count back to 3. Count each step as you go down.
   7, 6, 5, 4, 3
3. Count the steps. The number of steps is the missing number.
   5 steps
4. Write the answer.
   5

Check. Check: 3 + 5 = 8. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 4. Count back until you reach 0. The number of steps is the missing number.

1. Start at 4. That is the number we start with.
   4
2. Count back to 0. Count each step as you go down.
   3, 2, 1, 0
3. Count the steps. The number of steps is the missing number.
   4 steps
4. Write the answer.
   4

Check. Check: 0 + 4 = 4. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 10. Count back until you reach 4. The number of steps is the missing number.

1. Start at 10. That is the number we start with.
   10
2. Count back to 4. Count each step as you go down.
   9, 8, 7, 6, 5, 4
3. Count the steps. The number of steps is the missing number.
   6 steps
4. Write the answer.
   6

Check. Check: 4 + 6 = 10. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 7. Count back until you reach 2. The number of steps is the missing number.

1. Start at 7. That is the number we start with.
   7
2. Count back to 2. Count each step as you go down.
   6, 5, 4, 3, 2
3. Count the steps. The number of steps is the missing number.
   5 steps
4. Write the answer.
   5

Check. Check: 2 + 5 = 7. ✓

Watch out. Count the steps, not the numbers you say.

Method. Start at 9. Count back until you reach 3. The number of steps is the missing number.

1. Start at 9. That is the number we start with.
   9
2. Count back to 3. Count each step as you go down.
   8, 7, 6, 5, 4, 3
3. Count the steps. The number of steps is the missing number.
   6 steps
4. Write the answer.
   6

Check. Check: 3 + 6 = 9. ✓

Watch out. Count the steps, not the numbers you say.

Method. Add the number taken away to the answer. You should get the start.

1. Look at the answer. The answer is 3.
   3
2. Add the number taken away. Add back the 6 that was taken away.
   3 + 6
3. Check the total. The total is the start number.
   3 + 6 = 9
4. Write the answer.
   Accept any answer: 3 + 6 = 9, so 9 − 6 = 3 is right.

Check. 9 − 6 = 3, and 3 + 6 = 9. ✓

Watch out. Adding back should give the start number.