math help

What is 6/8 - 3/9?

What is 6/8 - 3/9?

Here's how to subtract 3/9 from 6/8:

6
8
3
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 6 by 9, and get 54.

Then we multiply 3 by 8, and get 24.

Next we give both terms new denominators -- 8 × 9 = 72.

So now our fractions look like this:

54
72
24
72

Step 2

Since our denominators match, we can subtract the numerators.

54 − 24 = 30

So the answer is:

30
72

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:

30
72
÷ 2 =
15
36

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:

15
36
÷ 3 =
5
12

Let's try dividing by 3 again...

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

Nope! So now we try the next greatest prime number, 7...

No good. 7 is larger than 5. So we're done reducing.

There you have it! The final answer is:
6
8
3
9
=
5
12