Skip to the main content
PeabodyMake a free story

➕ 1st grade math · Add & Subtract

Find the missing number

Think: what do I add to 3 to make 8? Take the part you know from the whole.

Worked example

Find the missing number: 2 + ? = 9
Answer: 7
Think: 2 + ? = 9. Take the part you know from the whole: 9 − 2 = 7. Answer: 7.

For grown-ups: Unknown in any position (8 + ? = 11). Below: three problems to try with the worked answers, and a free printable sheet. Children can practise the same skill as a game, with no sign-up and no ads.

  • CCSS 1.OA.D.8
What this practises, for teachers

Practices unknown in any position (8 + ? = 11) (1.OA.D.8). A printable sheet with its answer key, worked answers on the page, no accounts.

▶ Practise it

For your class

🖨️ Printable sheet and key

On the board with this skill:

More printables, with answer keys, for this grade:

Try three

  1. Find the missing number: 9 + ? = 10
    Show the answer and how
    Answer: 1
    Think: 9 + ? = 10. Take the part you know from the whole: 10 − 9 = 1. Answer: 1.
  2. Find the missing number: 3 + 2 = ?
    Show the answer and how
    Answer: 5
    Put them together: 3 + 2 = 5. Answer: 5.
  3. Find the missing number: 15 + ? = 16
    Show the answer and how
    Answer: 1
    Think: 15 + ? = 16. Take the part you know from the whole: 16 − 15 = 1. Answer: 1.

Before and after

Learn first: What the equal sign means (1st)

Name: ____________________Date: ____________Score: ____ / 12

Find the missing number (1st grade)

  1. Find the missing number: 1 + ? = 7
  2. Find the missing number: 8 + ? = 10
  3. Find the missing number: 4 + ? = 5
  4. Find the missing number: 2 + ? = 9
  5. Find the missing number: 6 + ? = 10
  6. Find the missing number: ? + 2 = 10
  7. Find the missing number: ? + 2 = 5
  8. Find the missing number: ? − 2 = 8
  9. Find the missing number: 9 + 1 = ?
  10. Find the missing number: 6 + 3 = ?
  11. Find the missing number: 15 + ? = 16
  12. Find the missing number: 13 + 4 = ?

Answer key

  1. 6
  2. 2
  3. 1
  4. 7
  5. 4
  6. 8
  7. 3
  8. 10
  9. 10
  10. 9
  11. 1
  12. 17

More 1st grade skills: all 1st grade math skills, or every grade at math skills.