math help

What is 9/60 + 3/7?

What is 9/60 + 3/7?

This is how you add

9
60
+
3
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 9 by 7, and get 63, then we multiply 60 by 7 and get 420.

9/60 times 7

Now for the second term. You multiply 3 by 60, and get 180, then multiply 60 by 7 and get 420.

3/7 times 60

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

63
420
+
180
420

Step 2

Since our denominators match, we can add the numerators.

63 + 180 = 243

That gives us the sum, which is

243
420

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...

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

243
420
÷ 3 =
81
140

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...

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...

No good. 83 is larger than 81. So we're done reducing.

Congratulations! Here's your final answer to 9/60 + 3/7

9
60
+
3
7
=
81
140
© 2014 Randy Tayler