What is 100/12 + 25/15?

Here's how you add

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. 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 100 by 15, and get 1500, then we multiply 12 by 15 and get 180.

Do the same for the second term. We multiply 25 by 12, and get 300, then multiply 12 by 15 and get 180.

So now our fractions look like this:

Step 2

Since our denominators match, we can add the numerators.

1500 + 300 = 1800

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...

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

So far so good... let's try to divide by that number again.

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

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

So far so good... let's try to divide by that number again.

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 5...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

So far so good... let's try to divide by that number again.

No good. 5 is larger than 1. So we're done reducing.

And we're done! Here's the final answer to 100/12 + 25/15