Three-Digit Addition & Subtraction — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
532 - 278 = 264.
Corrected: 532 - 278 = 254 because when borrowing from the tens place, 12 - 8 = 4, then 2 - 7 requires borrowing again.
The corrected sentence is: "532 - 278 = 254 because when borrowing from the tens place, 12 - 8 = 4, then 2 - 7 requires borrowing again.". The original sentence "532 - 278 = 264." contained an error that needed to be fixed.
2. Fix the sentence:
614 - 357 = 367.
Corrected: 614 - 357 = 257 because 14 - 7 = 7, 0 - 5 requires borrowing so 10 - 5 = 5, then 5 - 3 = 2.
The corrected sentence is: "614 - 357 = 257 because 14 - 7 = 7, 0 - 5 requires borrowing so 10 - 5 = 5, then 5 - 3 = 2.". The original sentence "614 - 357 = 367." contained an error that needed to be fixed.
3. Fix the sentence:
800 - 456 = 454.
Corrected: 800 - 456 = 344 because you must borrow across zeros, giving 7-9-10 minus 4-5-6.
The corrected sentence is: "800 - 456 = 344 because you must borrow across zeros, giving 7-9-10 minus 4-5-6.". The original sentence "800 - 456 = 454." contained an error that needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 745 - 312 = 433.
745 - 312 = 433. Subtract ones: 5 - 2 = 3. Subtract tens: 4 - 1 = 3. Subtract hundreds: 7 - 3 = 4.
2. 963 - 548 = 415.
963 - 548 = 415. Subtract ones: 13 - 8 = 5 (borrow from tens). Subtract tens: 5 - 4 = 1. Subtract hundreds: 9 - 5 = 4.
3. 500 - 237 = 263.
500 - 237 = 263. Borrow across zeros: 500 becomes 4-9-10. Subtract ones: 10 - 7 = 3. Subtract tens: 9 - 3 = 6. Subtract hundreds: 4 - 2 = 2.
4. 871 - 459 = 412.
871 - 459 = 412. Subtract ones: 11 - 9 = 2 (borrow from tens). Subtract tens: 6 - 5 = 1. Subtract hundreds: 8 - 4 = 4.
Part C: True or False?
Read each statement. Circle True or False.
1. When subtracting 634 - 289, you need to borrow from the tens place first.
True False
The statement is true based on the subtraction calculation.
2. 900 - 350 = 650.
True False
The statement is false; check the subtraction carefully.
3. The difference between 756 and 431 is 325.
True False
The statement is true based on the subtraction calculation.