math help

What is 11/20 + 1/8?

What is 11/20 + 1/8?

Here's how you add

11
20
+
1
8

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 11 by 8, and get 88, then we multiply 20 by 8 and get 160.

11/20 times 8

Do the same for the second term. We multiply 1 by 20, and get 20, then multiply 20 by 8 and get 160.

1/8 times 20

So now our fractions look like this:

88
160
+
20
160

Step 2

Since our denominators match, we can add the numerators.

88 + 20 = 108

So the answer is:

108
160

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

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

108
160
÷ 2 =
54
80

Now, try the same number again.

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

54
80
÷ 2 =
27
40

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...

No good. 29 is larger than 27. So we're done reducing.

Congratulations! Here's your final answer to 11/20 + 1/8

11
20
+
1
8
=
27
40
© 2014 Randy Tayler