What is 91/1 - 1/10?

Here's how to subtract 1/10 from 91/1:

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 1 by 1, and get 1.

Next we give both terms new denominators -- 1 × 10 = 10.

So now our fractions look like this:

Step 2

Since our denominators match, we can subtract the numerators.

910 − 1 = 909

So the answer is:

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...

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...

No good. 11 is larger than 10. So we're done reducing.