 # What is 1/2 - 3/10? Here's how to subtract 3/10 from 1/2:

 1 2
 3 10

## Step 1

We can't subtract two fractions with different denominators. So you need to get a common denominator. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 1 by 10, and get 10.

Then we multiply 3 by 2, and get 6.

Next we give both terms new denominators -- 2 × 10 = 20.

So now our fractions look like this:

 10 20
 6 20

## Step 2

Since our denominators match, we can subtract the numerators.

10 − 6 = 4

 4 20

## Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

 4 20
÷ 2 =
 2 10

Let's try dividing by 2 again...

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

 2 10
÷ 2 =
 1 5

Let's try dividing by 2 again...

No good. 2 is larger than 1. So we're done reducing.

There you have it! The final answer is:
 1 2
 3 10
=
 1 5