math help

What is 3/20 + 8/12?

What is 3/20 + 8/12?

Let's add

3
20
+
8
12

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 12, and get 36, then we multiply 20 by 12 and get 240.

3/20 times 12

Now for the second term. You multiply 8 by 20, and get 160, then multiply 20 by 12 and get 240.

8/12 times 20

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

36
240
+
160
240

Step 2

Since our denominators match, we can add the numerators.

36 + 160 = 196

Answer:

196
240

Step 3

Now, do we need to simplify this fraction?

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

196
240
÷ 2 =
98
120

Now, try the same number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

98
120
÷ 2 =
49
60

Now, try the same number again.

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...

No good. 53 is larger than 49. So we're done reducing.

Congratulations! Here's your final answer to 3/20 + 8/12

3
20
+
8
12
=
49
60
© 2014 Randy Tayler