math help

What is 3/20 + 1/7?

What is 3/20 + 1/7?

This is how we add

3
20
+
1
7

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 3 by 7, and get 21, then we multiply 20 by 7 and get 140.

3/20 times 7

Now for the second term. You multiply 1 by 20, and get 20, then multiply 20 by 7 and get 140.

1/7 times 20

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

21
140
+
20
140

Step 2

Since our denominators match, we can add the numerators.

21 + 20 = 41

That gives us the sum, which is

41
140

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...

No good. 43 is larger than 41. So we're done reducing.

Congratulations! Here's your final answer to 3/20 + 1/7

3
20
+
1
7
=
41
140
© 2014 Randy Tayler