Multiplying decimals · Usually met around P5
Multiplying by 0.1, 0.01 and 0.001
× 0.01 is ÷ 100: the point moves two places left.
How to do it
Method
× 0.01 is ÷ 100: the point moves two places left
35 × 0.01 = 35 ÷ 100 = 0.35
Another way
Count the places
35 × 1 = 35, two places → 0.35
In full
0.1 is 110, so multiplying by 0.1 is dividing by 10; by 0.01 is dividing by 100; by 0.001 is dividing by 1000. Way 1: move the decimal point one, two or three places left, filling with zeros in front if needed: 35 × 0.01 = 0.35, 4.2 × 0.001 = 0.0042. Way 2: multiply as whole numbers, then count decimal places: 35 × 1 = 35, and 0.01 has two places, so the product has two: 0.35. Multiplying by a number under 1 makes the product smaller than the number.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
533.28 × 0.01 = □
Show the answer and working
Answer: 5.3328
× 0.01 is ÷ 100: the point moves two places left, with zeros in front if needed: 5.3328.
Example 2
Which of these equals 244.61 × 0.01?
- A. 244.61 × 100
- B. 244.61 ÷ 1000
- C. 244.61 ÷ 10
- D. 244.61 ÷ 100
Choose the right answer
Show the answer and working
Answer: D. 244.61 ÷ 100
0.01 = 1100, so × 0.01 is ÷ 100.
Example 3
94.8 × 0.1 × 1000 = □
Show the answer and working
Answer: 9480
Left to right: × 0.1 moves the point left, × 1000 moves it right: 9480.
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