Three-Digit Addition and Subtraction — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A school collected 378 cans in October and 456 cans in November. They gave away 295 cans. How many cans do they have now?
A) 439
B) 539
C) 549
D) 639
First add 378 + 456 = 834 cans total. Then subtract the 295 given away: 834 - 295 = 539 cans remaining.
2. What is the best estimate for 627 - 384 when both numbers are rounded to the nearest hundred?
A) 100
B) 200
C) 300
D) 400
Round 627 to 600 and 384 to 400. Then 600 - 400 = 200, so the best estimate is 200.
3. Maya read 245 pages last week and 318 pages this week. Her goal is 700 pages. How many more pages does she need?
A) 127
B) 137
C) 147
D) 237
First add the pages Maya already read: 245 + 318 = 563. Then subtract from her goal: 700 - 563 = 137 more pages needed.
4. Which addition problem requires regrouping in both the ones and tens places?
A) 312 + 254
B) 475 + 368
C) 410 + 283
D) 521 + 136
In 475 + 368, the ones give 5 + 8 = 13 (regroup) and the tens give 7 + 6 + 1 = 14 (regroup again), so both places need regrouping.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 256 + 389 + 147 = 792.
Add the first two: 256 + 389 = 645. Then add the third: 645 + 147 = 792. You need to regroup in both steps.
2. A farmer harvested 843 apples. If 397 were sold at market, 446 apples remain.
Subtract 843 - 397: ones 3 < 7, borrow to get 13 - 7 = 6. Tens: 3 - 9 needs borrowing: 13 - 9 = 4. Hundreds: 7 - 3 = 4. So 446 apples remain.
3. 700 - 358 = 342.
700 has zeros in the ones and tens, so borrow across both: 10 - 8 = 2, 9 - 5 = 4, 6 - 3 = 3. The difference is 342.
4. The sum of 567 and 285 is 852.
Add ones: 7 + 5 = 12, carry 1. Tens: 6 + 8 + 1 = 15, carry 1. Hundreds: 5 + 2 + 1 = 8. The sum of 567 and 285 is 852.
5. 1000 - 472 = 528.
To subtract from 1000, borrow across all three zeros: 10 - 2 = 8, 9 - 7 = 2, 9 - 4 = 5. The difference is 528.