Adding & Subtracting Fractions — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A water bottle was 710 full. After drinking 310, how full is it now?
A) 420
B) 1010
C) 410
D) 310
Subtract the numerators: 7 − 3 = 4, and keep the denominator 10, so the bottle is 410 full.
2. Leo walked 216 miles to school and 146 miles back. What is the total distance?
A) 356 miles
B) 3512 miles
C) 416 miles
D) 136 miles
Add the wholes (2 + 1 = 3) and the sixths (16 + 46 = 56) to find Leo walked 356 miles total.
3. Maya had 58 of a ribbon and used 28 for a bow. What fraction is left?
A) 78
B) 316
C) 38
D) 28
Maya started with 58 and used 28, so subtract the numerators: 5 − 2 = 3, leaving 38 of the ribbon.
4. A recipe needs 324 cups of water. You already added 134 cups. How much more do you need?
A) 214 cups
B) 134 cups
C) 234 cups
D) 454 cups
Subtract what you added from what is needed: 324 − 134 requires regrouping, giving 134 cups still needed.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 38 + 58 = 88.
Add the numerators: 3 + 5 = 8, and the denominator stays 8, so the sum is 88 (which equals 1 whole).
2. 2512 + 1412 = 3912.
Add the wholes (2 + 1 = 3) and the twelfths (512 + 412 = 912) to get 3912.
3. 910 − 710 = 210.
Both fractions are tenths, so subtract the numerators: 9 − 7 = 2, giving 210.
4. 435 − 215 = 225.
Subtract the wholes (4 − 2 = 2) and the fifths (35 − 15 = 25) to get 225.
5. 26 + 36 + 16 = 66.
Add all three numerators: 2 + 3 + 1 = 6, with denominator 6, so the answer is 66 (one whole).