Find 1/4, 2/4, 1/3 and 3/4 of Numbers

In this activity, we will be working out 1/3, 1/4, 2/4, and 3/4 of numbers. 

 

We won't have pictures to help us, so we need to have a look at how we can work these out!

To solve these we divide by the denominator then we multiply by the numerator.

 

Key vocabulary:

Numerator - the first number (the top one) in a fraction. 

Denominator - the second number  (the bottom one) in a fraction. 

 

 

Let's start by looking at how we work out 1/4 and 1/3 of a number where the numerator is 1. 

 

1/4 of 12 = 

This means 12 needs to be split into four equal groups which can be written:

12 ÷ 4 = 

To work this out we need to work out how many 4s are in 12.

Let's count: 4, 8, 12.

That took three fours so our answer is three.

12 ÷ 4 = 3

The numerator is 1 so we are only looking at one group.

So 1/4 of 12 is 3

 

 

1/3 of 12 =

The denominator is three, so we need to divide by 3:

12 ÷ 3

Let's count in 3s until we reach 12:

3, 6, 9, 12

That took four threes. 

12 ÷ 3 = 4

The numerator is 1, so we are only looking at one group so this is our answer.

So 1/3 of 12 is 4

 

 

Now let's have a look at what we do when the numerator is bigger than 1:

 

2/4 of 12 = 

First, we look at the denominator and that is what we are dividing by, which is 4:

12 ÷ 4 = 

To work this out we need to work out how many 4s are in 12.

Let's count: 4, 8, 12.

That took three fours so our answer is three.

12 ÷ 4 = 3

1/4 of 12 is 3

 

But as the numerator is 2, it means we are looking for 2/4, so now we need to multiply the answer by 2:

3 x 2 = 6

This means 2/4 of 12 is 6

 

3/4 of 28  = 

This time we are starting with 28

We look at the denominator and that is what we are dividing by, which is 4:

28 ÷ 4 =

To work this out we need to work out how many 4s are in 28.

Let's count: 4, 8, 12, 16, 20, 24, 28

That took seven fours so our answer is seven.

28 ÷ 4 = 7

1/4 of 28 is 7

 

But as the numerator is 3, it means we are looking for 3/4, so now we need to multiply the answer by 3:

7 x 3 = 21

3/4 of 28 = 21

 

Do you think you can give these questions a go?

 

Just remember, first we divide by the denominator then we multiply by the numerator.