Adding & Subtracting Fractions — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. What is 23 + 23 written as a mixed number?
A) 46
B) 43
C) 113
D) 223
23 + 23 = 43, and since 43 is more than one whole, rewrite it as 1 and 13.
2. A plank is 315 meters long. You cut off 135 meters. How long is the remaining piece?
A) 135 meters
B) 225 meters
C) 235 meters
D) 125 meters
Regroup 315 as 265, then subtract: 265 − 135 = 135 meters remaining.
3. Kim drank 238 liters of water in the morning and 168 liters in the afternoon. How much total?
A) 398 liters
B) 418 liters
C) 318 liters
D) 498 liters
Add wholes (2 + 1 = 3) and eighths (38 + 68 = 98 = 118), then combine: 3 + 118 = 418 liters.
4. A tank holds 729 gallons. After using 359 gallons, how much is left?
A) 439 gallons
B) 369 gallons
C) 469 gallons
D) 339 gallons
Regroup 729 as 6119 so you can subtract: 6119 − 359 = 369 gallons left.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 67 + 37 = 97.
Add the numerators: 6 + 3 = 9, keeping the denominator 7, so the sum is 97 (an improper fraction greater than 1).
2. 3410 + 2510 = 5910.
Add wholes (3 + 2 = 5) and tenths (410 + 510 = 910) to get 5910.
3. 526 − 356 = 136.
Regroup 526 as 486 so you can subtract: 486 − 356 = 136.
4. 45 + 45 = 85.
Add the numerators: 4 + 4 = 8, with denominator 5, giving the improper fraction 85.
5. 614 − 234 = 324.
Regroup 614 as 554, then subtract: 554 − 234 = 324.