math help

What is 7/8 - 3/12?

What is 7/8 - 3/12?

Here's how to subtract 3/12 from 7/8:

7
8
3
12

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 7 by 12, and get 84.

Then we multiply 3 by 8, and get 24.

Next we give both terms new denominators -- 8 × 12 = 96.

So now our fractions look like this:

84
96
24
96

Step 2

Since our denominators match, we can subtract the numerators.

84 − 24 = 60

So the answer is:

60
96

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:

60
96
÷ 2 =
30
48

Let's try dividing by 2 again...

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

30
48
÷ 2 =
15
24

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
24
÷ 3 =
5
8

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:
7
8
3
12
=
5
8