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➕ 1st grade math · Add & Subtract

Subtract by adding on

3, 5 and 8 make 3 + 5 = 8, 5 + 3 = 8, 8 − 3 = 5, 8 − 5 = 3. If you know one fact, you know the family.

Worked example

Look at this fact: 6 + 5 = 11. Which fact is in the same fact family? (It uses the same three numbers: 5, 6, 11.)
Answer: 5 + 6 = 11
A fact family uses the same three numbers: 6, 5 and 11. 5 + 6 = 11 is in the family.

For grown-ups: Subtraction as an unknown addend. 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.B.4
What this practises, for teachers

Practices subtraction as an unknown addend (1.OA.B.4). A printable sheet with its answer key, worked answers on the page, no accounts.

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For your class

🖨️ Printable sheet and key

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More printables, with answer keys, for this grade:

Try three

  1. Look at this fact: 4 + 6 = 10. Which fact is in the same fact family? (It uses the same three numbers: 4, 6, 10.)
    Show the answer and how
    Answer: 10 − 6 = 4
    A fact family uses the same three numbers: 4, 6 and 10. 10 − 6 = 4 is in the family.
  2. Look at this fact: 11 + 9 = 20. Which fact is in the same fact family? (It uses the same three numbers: 9, 11, 20.)
    Show the answer and how
    Answer: 9 + 11 = 20
    A fact family uses the same three numbers: 11, 9 and 20. 9 + 11 = 20 is in the family.
  3. Look at this fact: 14 − 9 = 5. Which fact is in the same fact family? (It uses the same three numbers: 5, 9, 14.)
    Show the answer and how
    Answer: 14 − 5 = 9
    A fact family uses the same three numbers: 9, 5 and 14. 14 − 5 = 9 is in the family.
Name: ____________________Date: ____________Score: ____ / 12

Subtract by adding on (1st grade)

  1. These facts use the same three numbers (4, 8, 12): 8 + 4 = 12, 4 + 8 = 12, and 12 − 8 = 4. Find the missing number in the last fact: 12 − 4 = ?
  2. Look at this fact: 4 + 8 = 12. Which fact is in the same fact family? (It uses the same three numbers: 4, 8, 12.)
  3. Look at this fact: 7 − 2 = 5. Which fact is in the same fact family? (It uses the same three numbers: 2, 5, 7.)
  4. These facts use the same three numbers (1, 8, 9): 8 + 1 = 9, 1 + 8 = 9, and 9 − 8 = 1. Find the missing number in the last fact: 9 − 1 = ?
  5. These facts use the same three numbers (1, 5, 6): 5 + 1 = 6, 1 + 5 = 6, and 6 − 5 = 1. Find the missing number in the last fact: 6 − 1 = ?
  6. Look at this fact: 9 − 3 = 6. Which fact is in the same fact family? (It uses the same three numbers: 3, 6, 9.)
  7. Look at this fact: 6 + 3 = 9. Which fact is in the same fact family? (It uses the same three numbers: 3, 6, 9.)
  8. Look at this fact: 10 + 11 = 21. Which fact is in the same fact family? (It uses the same three numbers: 10, 11, 21.)
  9. Look at this fact: 4 + 9 = 13. Which fact is in the same fact family? (It uses the same three numbers: 4, 9, 13.)
  10. Look at this fact: 12 − 10 = 2. Which fact is in the same fact family? (It uses the same three numbers: 2, 10, 12.)
  11. Look at this fact: 10 + 5 = 15. Which fact is in the same fact family? (It uses the same three numbers: 5, 10, 15.)
  12. Look at this fact: 7 + 12 = 19. Which fact is in the same fact family? (It uses the same three numbers: 7, 12, 19.)

Answer key

  1. 8
  2. 12 − 8 = 4
  3. 7 − 5 = 2
  4. 8
  5. 5
  6. 6 + 3 = 9
  7. 9 − 3 = 6
  8. 21 − 10 = 11
  9. 13 − 4 = 9
  10. 2 + 10 = 12
  11. 15 − 5 = 10
  12. 19 − 12 = 7

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