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Grade 4 · Math · Unit 2 of 16

Add & Subtract

Big numbers, up to 10 000

What your child practises

Adding and subtracting numbers to 10 000 with regrouping, counting up to subtract, estimating by rounding, and solving word problems.

Ontario Curriculum expectation: B2.1, B2.4 · adding and subtracting whole numbers that add up to no more than 10 000

How we explain it

Children can open this short lesson before they practise.

  1. Line up the digits by place value.
  2. Work from the ones to the thousands.
  3. Regroup when a place has more than 9.

Example: 4 582 + 2 749 = ? Ones: 2 + 9 = 11. Write 1, regroup 1. Tens: 8 + 4 + 1 = 13. Write 3, regroup 1. Hundreds: 5 + 7 + 1 = 13. Write 3, regroup 1. Thousands: 4 + 2 + 1 = 7. Answer: 7 331

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    What number goes in the box?

    1645 + = 2200

    answer box

    Show answer

    555

    Hint: Think: what do you add to 1645 to make 2200? Count up from 1645: +5 → 1650, +50 → 1700, +300 → 2000, +200 → 2200. Then add up the jumps: 5 + 50 + 300 + 200.

  2. Question 2

    Estimate 4637 + 1153 by rounding each number to the nearest thousand.

    • 8000
    • 5000
    • 7000
    • 6000
    Show answer

    6000

    Hint: 4637 rounds to 5000 and 1153 rounds to 1000. 5000 + 1000 = 6000.

  3. Question 3

    A school collected 4145 cans in May and 648 cans in June. How many cans altogether?

    🥫
    • 4893
    • 4783
    • 3497
    • 4793
    Show answer

    4793

    Hint: Put the two amounts together: 4145 + 648. Add place by place: 4000 + 0 = 4000, 100 + 600 = 700, 40 + 40 = 80, 5 + 8 = 13. Then add those: 4000 + 700 + 80 + 13.

  4. Question 4

    What is 2822 + 481?

    2822 + 481 = ?

    answer box

    Show answer

    3303

    Hint: Add place by place: 2000 + 0 = 2000, 800 + 400 = 1200, 20 + 80 = 100, 2 + 1 = 3. Then add those: 2000 + 1200 + 100 + 3.

  5. Question 5

    What is 8671 − 6920?

    8671 − 6920 = ?

    • 2351
    • 1751
    • 1651
    • 1761
    Show answer

    1751

    Hint: Line up the places and start with the ones. If the top digit is too small, regroup 1 from the next place to the left. Check by adding your answer to 6920: you should get 8671.

  6. Question 6

    What is 6449 + 687?

    6449 + 687 = ?

    • 7136
    • 7146
    • 6026
    • 7036
    Show answer

    7136

    Hint: Add place by place: 6000 + 0 = 6000, 400 + 600 = 1000, 40 + 80 = 120, 9 + 7 = 16. Then add those: 6000 + 1000 + 120 + 16.

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