math help

What is 5/100 + 2/12?

What is 5/100 + 2/12?

Here's how to add

5
100
+
2
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 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 2 by 100, and get 200, then multiply 100 by 12 and get 1200.

2/12 times 100

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

60
1200
+
200
1200

Step 2

Since our denominators match, we can add the numerators.

60 + 200 = 260

That gives us the sum, which is

260
1200

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:

260
1200
÷ 2 =
130
600

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

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

130
600
÷ 2 =
65
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:

65
300
÷ 5 =
13
60

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. So next you try the next prime number, which is 17...

No good. 17 is larger than 13. So we're done reducing.

And we're done! Here's the final answer to 5/100 + 2/12

5
100
+
2
12
=
13
60
© 2014 Randy Tayler