math help

What is 5/100 + 4/12?

What is 5/100 + 4/12?

This is how you add

5
100
+
4
12

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 5 by 12, and get 60, then we multiply 100 by 12 and get 1200.

5/100 times 12

Now for the second term. You multiply 4 by 100, and get 400, then multiply 100 by 12 and get 1200.

4/12 times 100

This gives us a new problem that looks like so:

60
1200
+
400
1200

Step 2

Since our denominators match, we can add the numerators.

60 + 400 = 460

That gives us an answer of

460
1200

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:

460
1200
÷ 2 =
230
600

Now, try the same number again.

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

230
600
÷ 2 =
115
300

Now, try the same number again.

Nope. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

115
300
÷ 5 =
23
60

Now, try the same number again.

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 23. So we're done reducing.

Congratulations! Here's your final answer to 5/100 + 4/12

5
100
+
4
12
=
23
60
© 2014 Randy Tayler