math help

What is 3/20 + 8/9?

What is 3/20 + 8/9?

Here's how you add

3
20
+
8
9

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 3 by 9, and get 27, then we multiply 20 by 9 and get 180.

3/20 times 9

Do the same for the second term. We multiply 8 by 20, and get 160, then multiply 20 by 9 and get 180.

8/9 times 20

So now our fractions look like this:

27
180
+
160
180

Step 2

Since our denominators match, we can add the numerators.

27 + 160 = 187

So the answer is:

187
180

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. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

Nope. Try the next prime number, 67...

Nope. Try the next prime number, 71...

Nope. Try the next prime number, 73...

Nope. Try the next prime number, 79...

Nope. Try the next prime number, 83...

Nope. Try the next prime number, 89...

Nope. Try the next prime number, 97...

Nope. Try the next prime number, 101...

Nope. Try the next prime number, 103...

Nope. Try the next prime number, 107...

Nope. Try the next prime number, 109...

Nope. Try the next prime number, 113...

Nope. Try the next prime number, 127...

Nope. Try the next prime number, 131...

Nope. Try the next prime number, 137...

Nope. Try the next prime number, 139...

Nope. Try the next prime number, 149...

Nope. Try the next prime number, 151...

Nope. Try the next prime number, 157...

Nope. Try the next prime number, 163...

Nope. Try the next prime number, 167...

Nope. Try the next prime number, 173...

Nope. Try the next prime number, 179...

Nope. Try the next prime number, 181...

No good. 181 is larger than 180. So we're done reducing.

Congratulations! Here's your final answer to 3/20 + 8/9

3
20
+
8
9
=
187
180
© 2014 Randy Tayler