4th grade · Math · Unit 2 of 15
Add & Subtract
Big numbers, up to 10,000
What your child practices
Adding and subtracting numbers to 10,000 with regrouping, counting up to subtract, estimating by rounding, and solving word problems.
Oregon State Standards learning standard: 4.NBT.B.4 · fluently adding and subtracting multi-digit whole numbers
How we explain it
Children can open this short lesson before they practice.
- Line up the digits by place value.
- Work from the ones to the thousands.
- 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.
Question 1
What number goes in the box?
1645 + = 2200
answer box
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.
Question 2
Estimate 4637 + 1153 by rounding each number to the nearest thousand.
- 8000
- 5000
- 7000
- 6000
6000
Hint: 4637 rounds to 5000 and 1153 rounds to 1000. 5000 + 1000 = 6000.
Question 3
A school collected 4145 cans in May and 648 cans in June. How many cans altogether?
🥫- 4893
- 4783
- 3497
- 4793
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.
Question 4
What is 2822 + 481?
2822 + 481 = ?
answer box
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.
Question 5
What is 8671 − 6920?
8671 − 6920 = ?
- 2351
- 1751
- 1651
- 1761
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.
Question 6
What is 6449 + 687?
6449 + 687 = ?
- 7136
- 7146
- 6026
- 7036
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.