Inverse: addition undoes subtraction · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Addition and subtraction undo each other

Mathematics · Addition & Subtraction · ages 6-7
Name ______________________   Date ____________

  1. Addition and subtraction are opposites. What does that mean?

    • They always give the same answer
    • One undoes what the other does
    • They are not related at all

  2. Ann checks 12 + 5 = 17 using 17 - 5. What should she get?

    • 5
    • 22
    • 7
    • 12

  3. ? + 9 = 14. What is the missing number?

    Answer: ______________

  4. If 12 + 6 = 18, what does 18 − 6 equal?

    67891011121314151617181920+6
    • 6
    • 12
    • 18

  5. Kim checks 14 + 6 = 20 with 20 - 6 = 14. Is her check right?

    Circle one:   True   False

  6. ? + 6 = 13. What is the missing number?

    • 7
    • 6
    • 8
    • 19

  7. 15 + 7 = 22. To check, work out 22 - 7. What do you get?

    Answer: ______________

  8. Tom worked out 20 − 6 = 14. Which sum can he use to check it?

    • 14 + 6
    • 20 + 6
    • 20 − 14

  9. Ravi worked out 16 + 9 = 25. He checked it with 25 − 9 and got 15. What went wrong?

    • Nothing, both answers are right
    • His addition, 16 + 9, is wrong
    • His check, 25 − 9, is wrong

  10. Max says 25 - 25 + 25 = 25. Is Max right?

    Circle one:   True   False

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Answer key

For grown-ups. Fold this page away before handing over the rest.

Addition and subtraction undo each other W1-mt_ehGS_uVSJv-s1

  1. One undoes what the other does · If you add a number and then subtract that same number, you end up back where you started.
  2. 12 · 17 - 5 = 12, which matches the start.
  3. 5 · 14 - 9 = 5.
  4. 12 · Subtracting 6 undoes the addition, so you land back on 12.
  5. True · Kim is right: 20 - 6 = 14.
  6. 7 · 13 - 6 = 7.
  7. 15 · 22 - 7 = 15, which matches the start.
  8. 14 + 6 · Addition undoes subtraction. If 14 + 6 gets back to 20, the subtraction was right.
  9. His check, 25 − 9, is wrong · 16 + 9 = 25 is correct. But 25 − 9 = 16, not 15, so the mistake is in the check.
  10. True · Max is right: 25 - 25 = 0, and 0 + 25 = 25.
Worksheet · LightMySky