math help

What is 20/17 + 3/9?

What is 20/17 + 3/9?

Here's how to add

20
17
+
3
9

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 20 by 9, and get 180, then we multiply 17 by 9 and get 153.

20/17 times 9

Now for the second term. You multiply 3 by 17, and get 51, then multiply 17 by 9 and get 153.

3/9 times 17

This gives us a new problem that looks like so:

180
153
+
51
153

Step 2

Since our denominators match, we can add the numerators.

180 + 51 = 231

That gives us an answer of

231
153

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

Nope. Try the next prime number, 3...

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

231
153
÷ 3 =
77
51

Now, try the same number again.

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...

No good. 53 is larger than 51. So we're done reducing.

Congratulations! Here's your final answer to 20/17 + 3/9

20
17
+
3
9
=
77
51
© 2014 Randy Tayler