 # What is 8/12 - 4/10? Here's how to subtract 4/10 from 8/12:

 8 12
 4 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 8 by 10, and get 80.

Then we multiply 4 by 12, and get 48.

Next we give both terms new denominators -- 12 × 10 = 120.

So now our fractions look like this:

 80 120
 48 120

## Step 2

Since our denominators match, we can subtract the numerators.

80 − 48 = 32

So the answer is:

 32 120

## 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:

 32 120
÷ 2 =
 16 60

Let's try dividing by 2 again...

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

 16 60
÷ 2 =
 8 30

Let's try dividing by 2 again...

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

 8 30
÷ 2 =
 4 15

Let's try dividing by 2 again...

Nope! So now we try the next greatest prime number, 3...

Nope! So now we try the next greatest prime number, 5...

No good. 5 is larger than 4. So we're done reducing.

There you have it! The final answer is:
 8 12
 4 10
=
 4 15