math help

What is 3/20 + 6/8?

What is 3/20 + 6/8?

This is how you add

3
20
+
6
8

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 3 by 8, and get 24, then we multiply 20 by 8 and get 160.

3/20 times 8

Now for the second term. You multiply 6 by 20, and get 120, then multiply 20 by 8 and get 160.

6/8 times 20

This gives us a new problem that looks like so:

24
160
+
120
160

Step 2

Since our denominators match, we can add the numerators.

24 + 120 = 144

So what's the answer so far?

144
160

Step 3

Can this fraction be reduced?

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

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

144
160
÷ 2 =
72
80

Now, try the same number again.

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

72
80
÷ 2 =
36
40

Now, try the same number again.

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

36
40
÷ 2 =
18
20

Now, try the same number again.

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

18
20
÷ 2 =
9
10

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...

No good. 11 is larger than 9. So we're done reducing.

Congratulations! Here's your final answer to 3/20 + 6/8

3
20
+
6
8
=
9
10
© 2014 Randy Tayler