6th Grade Multi-Digit and Decimal Operations Quiz: 10 Questions with Explanations

A 228B 218C 238D 2,280

\(16 \times 200 = 3,200\), \(16 \times 28 = 448\), so 228. Check: \(228 \times 16 = 3,648\).

A 16.83B 17.15C 17.83D 60.5

Line up the decimal points: \(4.80 + 12.35 = 17.15\). Aligning to the right gives the wrong sums.

A 4.2B 0.042C 1.3D 0.42

\(6 \times 7 = 42\) and there are 2 decimal places, so 0.42.

A 9.28B 9.72C 8.72D 8.28

\(15.00 – 6.28 = 8.72\). A borrowing slip gives 9.72.

A 90B 9C 0.9D 900

Multiply both by 100: \(540 \div 6 = 90\).

A $0.42B $4.20C $42.00D $3.50

\(0.35 \times 12 = 4.20\). Misplacing the decimal gives $42.00.

A \(7.2 \div 0.8 = 0.9\)B \(7.2 \div 0.8 = 9\)C \(7.2 \div 0.8 = 90\)D \(7.2 \div 0.8 = 5.76\)

\(72 \div 8 = 9\). Dividing by 0.8 makes the quotient larger than \(7.2 \div 8\).

A 10B 25C 1,000D 100

48.7 is about 50, and 0.51 is about 0.5; \(50 \div 0.5 = 100\).

A 6B 0.6C 60D 8.75

\(0.75 \times 8 = 6\).

A 27B 38.25C 17D 24

\(25.5 \div 1.5 = 255 \div 15 = 17\).