math help

What is 7/20 + 3/7?

What is 7/20 + 3/7?

This is how you add

7
20
+
3
7

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 7 by 7, and get 49, then we multiply 20 by 7 and get 140.

7/20 times 7

Now for the second term. You multiply 3 by 20, and get 60, then multiply 20 by 7 and get 140.

3/7 times 20

This gives us a new problem that looks like so:

49
140
+
60
140

Step 2

Since our denominators match, we can add the numerators.

49 + 60 = 109

So what's the answer so far?

109
140

Step 3

Can this fraction be reduced?

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...

No good. 113 is larger than 109. So we're done reducing.

Congratulations! Here's your final answer to 7/20 + 3/7

7
20
+
3
7
=
109
140
© 2014 Randy Tayler