5th Grade Adding and Subtracting Decimals Quiz: 10 Questions with Explanations

A 1.3B 0.13C 1.03D 13

6 tenths plus 7 tenths is 13 tenths, which is 1.3.

A 2.80B 6.80C 7.85D 6.85

Write 4.5 as 4.50. Then 4.50 + 2.35 = 6.85. Lining up the right-most digits gives the wrong answer 2.80.

A 5.38B 4.62C 5.62D 4.72

Write 7 as 7.00. Then 7.00 − 2.38 = 4.62. Check: 4.62 + 2.38 = 7.00.

A 13.28B 12.88C 13.12D 14.12

Write 20.5 as 20.50. Then 20.50 − 7.38 = 13.12.

A 14B 23C 24D 240

18.7 rounds to 19 and 5.34 rounds to 5. 19 + 5 = 24.

A Line up the last digitsB Line up the decimal pointsC Round both numbers to tensD Subtract the smaller number from the larger

Digits with the same place value must be in the same column, so the decimal points must line up.

A $7.54B $6.54C $7.44D $75.40

3.49 + 1.75 = 5.24 and 5.24 + 2.30 = 7.54.

A $7.32B $6.32C $6.68D $6.42

20.00 − 13.68 = 6.32. Check: 6.32 + 13.68 = 20.00.

A 17.95 inchesB 17.57 inchesC 18.95 inchesD 14.95 inches

14.20 + 3.75 = 17.95. Write 14.2 as 14.20 so the places line up.

A 0.73B 0.083C 8.3D 0.83

0.45 + 0.38 = 0.83. That is 83 hundredths.