# Multiply 1-digit numbers by decimals

I can explain how to use multiplying and dividing by 10 or 100 to multiply 1-digit numbers by decimal fractions.

# Multiply 1-digit numbers by decimals

I can explain how to use multiplying and dividing by 10 or 100 to multiply 1-digit numbers by decimal fractions.

## Lesson details

### Key learning points

- Use place value to convert the decimal fraction by multiplication to a whole number.
- Use unitising, known facts and/or the distributive law to multiply the whole numbers.
- Use place value to convert the number by division to adjust the product.

### Common misconception

Children may scale the decimal fraction inaccurately or may forget to scale the product accordingly to solve the original equation.

If a decimal fraction has only tenths, we multiply by 10 to form a whole number. If the decimal fraction has hundredths, we multiply by 100 to form a whole number. Remember to adjust the product to answer the original equation.

### Keywords

Unitising - Treating groups that contain the same number of things as ‘ones’ or ‘units’. It is important particularly in handling money and in understanding place value and supports us to think multiplicatively.

Distributive law - The distributive law says that multiplying a number by a group of numbers added together is the same as doing each multiplication separately.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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## Starter quiz

### 6 Questions

30

140

1030

21

5

4

15

1.5

0.4

0.04

53 ÷ 10

53 ÷ 100

53 ÷ 1

5.3 ÷ 10

5.3 ÷ 100

## Exit quiz

### 6 Questions

0.32

0.42

4.5

1.2

2.4