math help

What is 100/50 + 5/12?

What is 100/50 + 5/12?

This is how to add

100
50
+
5
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 100 by 12, and get 1200, then we multiply 50 by 12 and get 600.

100/50 times 12

Now for the second term. You multiply 5 by 50, and get 250, then multiply 50 by 12 and get 600.

5/12 times 50

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

1200
600
+
250
600

Step 2

Since our denominators match, we can add the numerators.

1200 + 250 = 1450

That gives us the sum, which is

1450
600

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:

1450
600
÷ 2 =
725
300

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 3...

No good. So next you try the next prime number, which is 5...

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

725
300
÷ 5 =
145
60

So far so good... let's try to divide by that number again.

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

145
60
÷ 5 =
29
12

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. 13 is larger than 12. So we're done reducing.

And we're done! Here's the final answer to 100/50 + 5/12

100
50
+
5
12
=
29
12
© 2014 Randy Tayler