What is 10/11 - 9/10?

Here's how to subtract 9/10 from 10/11:

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 10 by 10, and get 100.

Then we multiply 9 by 11, and get 99.

Next we give both terms new denominators -- 11 × 10 = 110.

So now our fractions look like this:

Step 2

Since our denominators match, we can subtract the numerators.

100 − 99 = 1

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...

No good. 2 is larger than 1. So we're done reducing.