math help

What is 91/6 - 9/10?

What is 91/6 - 9/10?

Here's how to subtract 9/10 from 91/6:

91
6
9
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 91 by 10, and get 910.

Then we multiply 9 by 6, and get 54.

Next we give both terms new denominators -- 6 × 10 = 60.

So now our fractions look like this:

910
60
54
60

Step 2

Since our denominators match, we can subtract the numerators.

910 − 54 = 856

So the answer is:

856
60

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:

856
60
÷ 2 =
428
30

Let's try dividing by 2 again...

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

428
30
÷ 2 =
214
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...

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

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

No good. 17 is larger than 15. So we're done reducing.

There you have it! The final answer is:
91
6
9
10
=
214
15