math help

What is 7/20 + 7/9?

What is 7/20 + 7/9?

Let's add

7
20
+
7
9

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 7 by 9, and get 63, then we multiply 20 by 9 and get 180.

7/20 times 9

Now for the second term. You multiply 7 by 20, and get 140, then multiply 20 by 9 and get 180.

7/9 times 20

We now have a new problem, that looks like this:

63
180
+
140
180

Step 2

Since our denominators match, we can add the numerators.

63 + 140 = 203

Answer:

203
180

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide 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 7/20 + 7/9

7
20
+
7
9
=
203
180
© 2014 Randy Tayler