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How to Find a Fraction of a Number (Mathematics Lesson)

Finding a Fraction of a Number

A fraction of a number lets us find part of a number.

Imagine 3/5 (three-fifths) of a class of 25 students love mathematics.

15 students (3/5 of 25) love mathematics.

How to Find the Fraction of a Number

To find the fraction of a number you have to multiply the fraction by the number:



Hint: 'of' means '×' when finding a fraction of a number.

A Real Example of How to Find the Fraction of a Number


An Example Question

What is 35 of 25?
Step 1
Write a fraction of a number as a fraction × a number, like the formula above.

In our example, the fraction is 35 and the number is 25.



Step 2
Divide the top number (called the numerator) of the fraction (3) by the bottom number (called the denominator) of the fraction (5).


3 ÷ 5 = 0.6
Step 3
Multiply the answer (0.6) by the number (25).

0.6 × 25 = 15
We have an answer:

Another Real Example of How to Find a Fraction of a Number

The slider below shows another example of finding a fraction of a number:
Interactive Test
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Here's a second test on finding a fraction of a number.
Here's a third test on finding a fraction of a number.
Top Tip

Fraction of Number =
Fraction × Number

When you see a question like:

Find 12 of 10

Translate of into ×:

12 × 10

Order of × and ÷ Doesn't Matter

In the example shown on this page, you:
  • find numerator ÷ denominator, then
  • × the number.
It is equally correct to do this the other way round:
  • find numerator × the number, then
  • ÷ by the denominator.

Multiplying a Number by a Mixed Fraction

The method used on this page is only suitable for:
It is not suitable for:
For example, if you wanted to find a mixed fraction of a number, such as:



Convert the mixed fraction to an improper fraction and then follow the method shown here.