Addition and subtraction within 1000 · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Adding and subtracting big numbers

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

  1. What is 300 + 250?

    Answer: ______________

  2. What is 245 + 300?

    • 275
    • 545
    • 548
    • 445

  3. When you add the ones and get 13, what do you write in the ones place, and what do you carry?

    • 13, and carry nothing
    • 3, and carry 1 ten to the tens place
    • 1, and carry 3 to the tens place

  4. In the ones column, the top digit is too small to subtract. What do you do?

    • Borrow a ten from the next place
    • Write a zero and skip it
    • Subtract the top from the bottom instead

  5. What is 378 + 50?

    Answer: ______________

  6. A drawing shows 5 hundred-blocks, 14 ten-blocks, and 3 ones. What should you do before reading the number?

    • Trade 10 tens for 1 hundred before reading the number
    • Keep 14 tens in the tens place and read the number as shown
    • Trade the 3 ones for tens before reading the number

  7. What is 700 - 250?

    • 550
    • 450
    • 540
    • 350

  8. 800 - 340 = 560.

    Circle one:   True   False

  9. Ben added 168 + 254 and wrote 322 because he forgot to carry the last hundred. What is the correct answer?

    • 412
    • 312
    • 422

  10. What is 900 - 375?

    Answer: ______________

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Answer key

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

Adding and subtracting big numbers W1-mt_ewmuMMPAzP-s1

  1. 550 · 300 + 200 = 500, then add the remaining 50 to get 550.
  2. 545 · 245 is 200 + 45. Adding 300 changes the hundreds part to 500, and 500 + 45 = 545.
  3. 3, and carry 1 ten to the tens place · 13 is 1 ten and 3 ones, so you write the 3 and carry the 1 ten to the tens column.
  4. Borrow a ten from the next place · Borrowing a ten from the next place gives you 10 more to work with, so you can subtract.
  5. 428 · 378 + 50 = 428. The 7 tens and 5 tens make 12 tens, which is 1 hundred and 2 tens.
  6. Trade 10 tens for 1 hundred before reading the number · 14 tens is more than 9, so trading 10 of them for 1 hundred lets you read the number correctly.
  7. 450 · Take away 200 to get 500. Then exchange 1 hundred for 10 tens and take away 5 tens to get 450.
  8. False · 800 - 300 = 500. Exchange 1 hundred for 10 tens, then take away 4 tens to get 460. The stated 560 keeps the hundred that was exchanged.
  9. 422 · Adding the hundreds column gives 1+2+1=4 hundreds, since carrying out of the tens adds one more hundred. The correct total is 422.
  10. 525 · Take away 300 to get 600. Then exchange 1 hundred for 10 tens and 1 ten for 10 ones, and take away 75 to get 525.
Worksheet · LightMySky