Calculate 3 1/4 - 1 1/2 Step by Step

Step by step

The question

Question: work out 3 and 1/4 − 1 and 1/2.

314 − 112

1 Make one fraction

3 and 1/4 is a mixed number.

Each whole one is 4/4.

So we do 3 times 4, plus 1.

The bottom stays 4.

= 3 × 4 + 14 − 112

3 times 4 plus 1 is 13.

So it is 13/4.

= 134 − 112

1 and 1/2 is a mixed number.

Each whole one is 2/2.

So we do 1 times 2, plus 1.

The bottom stays 2.

= 134 − 1 × 2 + 12

1 times 2 plus 1 is 3.

So it is 3/2.

= 134 − 32

2 Make the bottoms the same

The bottom numbers are 4 and 2.

They are different, so we can't take away the tops yet.

We count up in 4s and in 2s.

4 is the first number in both lists.

So 4 will be the new bottom.

In 4s: 4

In 2s: 2, 4

13/4 already has 4 at the bottom.

2 times 2 is 4.

So 3/2 gets times 2/2.

2 × 2 = 4

We multiply the top and the bottom by the same number.

= 134 − 32 × 22

2/2 is 1.

Times 1 does not change the size.

So the fraction stays the same, only the bottom changes.

22 = 1

Top times top.

Bottom times bottom.

= 134 − 3 × 22 × 2

3 times 2 is 6.

2 times 2 is 4.

Now both have 4 at the bottom.

= 134 − 64

3 Take away the tops

The bottoms are the same, so the pieces are the same size.

We take away the tops.

The bottom stays 4, because the size of the pieces does not change.

= 13 − 64

13 minus 6 is 7.

= 74

4 Write as a mixed number

7 divided by 4 is 1, with 3 left over.

So it is 1 and 3/4.

= 134

So the answer is 1 and 3/4.

Let's look back.

First: make one fraction.

Then: make the bottoms the same.

Then: take away the tops.

Last: write as a mixed number.

Answer