5th Grade Multiplying and Dividing Decimals Quiz: 10 Questions with Explanations

A \(0.4 \times 0.6 = 2.4\)B \(0.4 \times 0.6 = 0.024\)C \(0.4 \times 0.6 = 24\)D \(0.4 \times 0.6 = 0.24\)

The overlap has 4 x 6 = 24 squares out of 100, so the product is 0.24. The mistake is placing the decimal point wrongly.

A 1.56B 15.6C 0.156D 156

52 x 3 = 156. The factors have 1 + 1 = 2 decimal places, so the product is 1.56.

A 0.02B 0.2C 2D 0.002

25 x 8 = 200 with 3 decimal places is 0.200, which equals 0.2. Many students forget that trailing zeros can be dropped.

A 2.04B 24C 0.24D 2.4

96 / 4 = 24, and keeping the decimal point in line gives 2.4. Writing 2.04 inserts an extra zero.

A 0.8B 0.008C 0.08D 8

56 / 7 = 8. Since 0.56 has hundredths, the answer is 8 hundredths, or 0.08.

A 0.7B 7C 70D 1.75

Multiply both by 10: 35 / 5 = 7. Dividing by a number less than 1 gives a larger quotient.

A \(42 \div 6\)B \(420 \div 6\)C \(4.2 \div 6\)D \(4{,}200 \div 6\)

0.06 has 2 decimal places, so multiply both numbers by 100: 4.2 becomes 420 and 0.06 becomes 6.

A $7.20B $6.30C $72.00D $0.72

1.5 x 4.80 = 7.20. Adding the numbers gives $6.30, which is the typical mistake.

A 3.6 square feetB 3.9 square feetC 36 square feetD 0.36 square feet

24 x 15 = 360 with 2 decimal places is 3.60, so the area is 3.6 square feet. Adding the sides gives 3.9, which is perimeter work.

A 80 sectionsB 0.8 sectionC 8 sectionsD 6.3 sections

7.2 / 0.9 = 72 / 9 = 8. Subtracting gives 6.3, which is the wrong operation.