Decimals Quiz

15 questions · free · new questions every attempt · Updated September 26, 2026

Decimals appear in money, measurements and data, so being able to add, round and convert them matters every day. This quiz checks the essentials and gives an explanation after each answer, so you can see exactly how the decimal point should move.

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What this quiz covers

Adding and subtracting decimals
Multiplying a decimal by a whole number
Rounding to the nearest tenth
Converting a fraction to a decimal
Converting a decimal to a percent
Checking whether an answer is reasonable

How to prepare

Line up the decimal points when adding or subtracting and pad with zeros if needed. When multiplying, ignore the point, multiply as whole numbers, then put the point back so the answer has as many decimal places as the factors combined. To turn a decimal into a percent, multiply by 100.

Sample questions with answers

These five questions show the style. Your quiz above will have different numbers each time.

4.8 + 7.6 = ?
Show answer
12.4. Line up the decimal points: the answer is 12.4.
0.5 × 7 = ?
Show answer
3.5. 5 × 7 = 35, then divide by 10: 3.5.
Round 3.508 to the nearest tenth.
Show answer
3.5. Look at the hundredths digit to decide: 3.508 ≈ 3.5.
Write 9/20 as a decimal.
Show answer
0.45. 9 ÷ 20 = 0.45.
Write 0.75 as a percent.
Show answer
75%. Multiply by 100: 0.75 × 100 = 75%.