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Multiplying Decimals

Practise multiplying decimals — multiply as if there were no points, then count the decimal places to place the point.

Grades 5–6 · 5.NBT⚡ Decimal operations
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How to multiply decimals

Multiplying decimals has a neat trick: ignore the points, multiply the numbers as whole numbers, then put the point back by counting decimal places. Unlike addition, you do not line up the points first.

  1. Multiply the numbers as if they had no decimal points.
  2. Count the total number of decimal places in both factors.
  3. Put that many decimal places into the answer, counting from the right.

Worked examples

Decimal × whole1.2 × 3 — ignore the point: 12 × 3 = 36. One decimal place, so: 3.6.
Decimal × decimal0.3 × 0.4 — ignore points: 3 × 4 = 12. Two decimal places total, so: 0.12.
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Tips & common mistakes

The surprising part for kids is that 0.3 × 0.4 = 0.12, which is smaller than either number — multiplying by a number less than 1 shrinks things. Counting the decimal places is what gets the point in the right spot, so do it carefully.

  • Lining up the decimal points first (that’s for adding, not multiplying).
  • Miscounting the total decimal places — it’s the sum from both factors.
  • Being surprised the answer is smaller — with decimals under 1, that’s correct.

Frequently asked questions

How do you multiply decimals?

Multiply as whole numbers ignoring the points, then count the total decimal places in both factors and put that many into the answer.

Why is 0.3 × 0.4 only 0.12?

Because multiplying by a number less than 1 makes the result smaller. Three tenths of four tenths is just twelve hundredths.

Do I line up the decimal points?

No — that’s for adding and subtracting. For multiplying, you place the point afterward by counting decimal places.

How do I type my answer?

Use the number keys and the decimal-point key, e.g. 0 . 1 2.

What grade is multiplying decimals?

It is introduced in grade 5 and extended in grade 6.

Keep practising

← All decimalsAdding decimalsWhole-number multiplication5th grade math