# Math Help: How to Work Out a Fraction of a Number

Updated on February 8, 2018 ## Fraction Of Something Video

To work out a fraction of a number all you need to do is divide the number by the denominator of the fraction and multiply this answer by the numerator.

Example 1

Work out 3/8 of 48.

First of all divide 48 by the denominator:

48 ÷ 8 = 6 (this gives 1/8 of 48)

Now multiply this answer by the numerator:

6 × 3 = 18 (this gives 3/8 of 48)

Example 2

Work out 2/9 of 36.

First of all divide 36 by the denominator:

36 ÷ 9 = 4 (this gives 1/9 of 36)

Now multiply this answer by the numerator:

4 × 2 = 8 (this gives 2/9 of 36)

Example 3

Work out 4/5 of 60.

First of all divide 60 by the denominator:

60 ÷ 5 = 12 (this gives 1/5 of 60)

Now multiply this answer by the numerator:

12 × 4 = 48 (this gives 4/5 of 60)

Example 4

Work out 5/11 of 77.

First of all divide 77 by the denominator:

77 ÷ 11 = 7 (this gives 1/11 of 77)

Now multiply this answer by the numerator:

7 × 5 = 35 (this gives 5/11 of 77)

Example 5

A fuel tank holds 14 gallons of fuel when full. If the tank has 3/7 of fuel left in the tank, work out how many gallons of fuel are left.

Here you need to calculate 3/7 of 14 gallons

First of all divide 14 by the denominator:

14 ÷ 7 = 2 (this gives 1/7 of 14)

Now multiply this answer by the numerator:

2 × 3 = 6 (this gives 3/7 of 14)

So there are 6 gallons of fuel left in the tank.

• 12 is 3/4 of what number?

You need to divide by the top and multiply by the bottom.

12 divided by 3 is 4, and 4 times 4 is 16.

• What part of 5 3/5 is 7/10?

You will need to divide 7/10 by 5 3/5.

Convert 5 3/5 into an improper fraction which is 28/5

Now work out 7/10 divide by 28/5 which is the same as 7/10 times.

• What is 1/7 of 3.50?

Just divide 3.50 by 7 as 1/7 means divide by 7. This will give an anwer of 0.5.

• What is 48 minus 3/4 ?

Change 3/4 to a decimal to give 0.75.

Now work out 48 minus 0.75 to give 47.25.

• What is 7/8 of 48kg?

Follow the rule divide by the bottom and times by the top.

48 divided by 8 is 6, and 6 multiplied by 7 is 42.

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• Offenderman

21 months ago

Rose? Anyone?

• bum face

6 years ago

Thanks this helped!!! Xxxxxx

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