Multiplication With Decimals

Objective

Know how to multiply numbers with decimals

Example

2 4 3

1 2 2

4 6 5

5.8 7

x 5 3.8

4 6 9 6

1 7 6 1 0

+ 2 9 3 5 0 0

3 1 5.8 0 6

Answer: 315.806

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Explanation

Multiplying with decimals is exactly like multiplying without decimals, except that you need to put a decimal point in your answer. How do you know where to put it? Count the number of places after the decimal point in both numbers. Looking at our example above once again:

5.8 7 2 places

x 5 3.8 + 1 place

3 places

Here there are 3 places after decimal points in our question, so our answer must have 3 places after the decimal point.

3 1 5.8 0 6 <==== 3 places

Answer: 315.806

To watch a Khan Academy video, Click Here.

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Examples

Example 1

2 4

1 2

5.8

x 5.3

1 7 4

+ 2 9 0 0

3 0.7 4

Answer: 30.74

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Example 2

2 4 3

1 2 2

0.5 8 7

x 5 3

1 7 6 1

+ 2 9 3 5 0

3 1.1 1 1

Answer: 31.111

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