math help

What is 8/12 - 8/9?

What is 8/12 - 8/9?

Here's how to subtract 8/9 from 8/12:

8
12
8
9

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 9, and get 72.

Then we multiply 8 by 12, and get 96.

Next we give both terms new denominators -- 12 × 9 = 108.

So now our fractions look like this:

72
108
96
108

Step 2

Since our denominators match, we can subtract the numerators.

72 − 96 = -24

So the answer is:

-24
108

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:

-24
108
÷ 2 =
-12
54

Let's try dividing by 2 again...

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

-12
54
÷ 2 =
-6
27

Let's try dividing by 2 again...

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

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

-6
27
÷ 3 =
-2
9

Let's try dividing by 3 again...

No good. 3 is larger than -2. So we're done reducing.

There you have it! The final answer is:
8
12
8
9
=
2
9