Mentally adding hundreds to 3-digit numbers · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Adding and subtracting hundreds in your head

Mathematics · Addition & Subtraction · ages 7-8
Name ______________________   Date ____________

  1. What is 762 − 400?

    Answer: ______________

  2. What is 345 + 200?

    • 547
    • 365
    • 545
    • 445

  3. What is 345 + 200?

    • 345
    • 365
    • 545

  4. In 762 - 400 = 362, only the hundreds digit changed.

    Circle one:   True   False

  5. What is 625 + 200?

    Answer: ______________

  6. Which number equals 483 - 200?

    • 283
    • 463
    • 481

  7. What is 458 + 300?

    • 788
    • 488
    • 658
    • 758

  8. Hana says 762 − 400 = 772. Is Hana right?

    Circle one:   True   False

  9. Leo says 372 + 400 = 472. What mistake did he make?

    • He replaced the hundreds digit instead of adding it
    • He added 4 to the ones digit
    • He forgot to add anything

  10. What is 200 more than 750?

    Answer: ______________

LightMySky · lightmysky.comW1-mt_xPqczp7zPX-s1

Answer key

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

Adding and subtracting hundreds in your head W1-mt_xPqczp7zPX-s1

  1. 362 · Taking 400 shrinks the 7 hundreds to 3 hundreds, giving 362.
  2. 545 · Adding 200 grows the 3 hundreds to 5 hundreds, giving 545.
  3. 545 · Only the hundreds digit changes: 3 + 2 = 5, so 345 becomes 545. The 4 and 5 stay the same.
  4. True · The 6 and 2 stayed the same digits. Only the 7 became a 3.
  5. 825 · Adding 200 grows the 6 hundreds to 8 hundreds, giving 825.
  6. 283 · 4 hundreds - 2 hundreds = 2 hundreds. The 8 and 3 stay put, so 483 - 200 = 283.
  7. 758 · Adding 300 grows the 4 hundreds to 7 hundreds, giving 758.
  8. False · Hana is wrong. Taking 400 shrinks the total to 362, not 772.
  9. He replaced the hundreds digit instead of adding it · 372 + 400 means 3 hundreds plus 4 more hundreds, which makes 7 hundreds: 772. Leo swapped in the 4 instead of adding it to the 3.
  10. 950 · Adding 200 grows the 7 hundreds to 9 hundreds, giving 950.
Worksheet · LightMySky