math help

What is 28/100 + 3/12?

What is 28/100 + 3/12?

This is how we add

28
100
+
3
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 28 by 12, and get 336, then we multiply 100 by 12 and get 1200.

28/100 times 12

Now for the second term. You multiply 3 by 100, and get 300, then multiply 100 by 12 and get 1200.

3/12 times 100

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

336
1200
+
300
1200

Step 2

Since our denominators match, we can add the numerators.

336 + 300 = 636

That gives us the sum, which is

636
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:

636
1200
÷ 2 =
318
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:

318
600
÷ 2 =
159
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...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

159
300
÷ 3 =
53
100

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 5...

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. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. So next you try the next prime number, which is 41...

No good. So next you try the next prime number, which is 43...

No good. So next you try the next prime number, which is 47...

No good. So next you try the next prime number, which is 53...

No good. So next you try the next prime number, which is 59...

No good. 59 is larger than 53. So we're done reducing.

And we're done! Here's the final answer to 28/100 + 3/12

28
100
+
3
12
=
53
100
© 2014 Randy Tayler