Three-Digit Addition & Subtraction — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A bakery made 534 muffins on Monday and 389 on Tuesday. They sold 476. How many muffins are left?
A) 437
B) 447
C) 457
D) 547
689 - 242 = 447. Subtract ones: 9 - 2 = 7. Subtract tens: 8 - 4 = 4. Subtract hundreds: 6 - 2 = 4.
2. What is the best estimate for 812 - 397 when both numbers are rounded to the nearest hundred?
A) 300
B) 400
C) 500
D) 600
756 rounds to 800 and 349 rounds to 400, so 800 - 400 = 400.
3. Ella reads 267 pages one week and 345 pages the next week. Her goal is 700 pages. How many more pages does she need?
A) 78
B) 88
C) 98
D) 108
547 - 459 = 88. Subtract ones: 17 - 9 = 8 (borrow from tens). Subtract tens: 3 - 5 requires borrowing: 13 - 5 = 8. Subtract hundreds: 4 - 4 = 0.
4. Which addition problem does NOT require regrouping in any place?
A) 456 + 378
B) 324 + 251
C) 189 + 467
D) 548 + 276
324 + 251 = 575. This is the addition problem that results in 575.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 256 + 478 + 139 = 873.
256 + 478 = 734, then 734 + 139 = 873.
2. A zoo has 514 visitors on Saturday and 379 on Sunday. The total is 893.
514 + 379 = 893. Add ones: 4 + 9 = 13, write 3 carry 1. Add tens: 1 + 7 + 1 = 9. Add hundreds: 5 + 3 = 8.
3. 900 - 563 = 337.
900 - 563 = 337. Borrow across zero: 900 becomes 8-9-10. Subtract ones: 10 - 3 = 7. Subtract tens: 9 - 6 = 3. Subtract hundreds: 8 - 5 = 3.
4. The difference between 742 and 385 is 357.
742 - 385 = 357. Subtract ones: 12 - 5 = 7 (borrow from tens). Subtract tens: 3 - 8 requires borrowing: 13 - 8 = 5. Subtract hundreds: 6 - 3 = 3.
5. 1000 - 482 = 518.
1000 - 482 = 518. Borrow across zeros: subtract ones: 10 - 2 = 8. Subtract tens: 9 - 8 = 1. Subtract hundreds: 9 - 4 = 5.