math help

What is 72/63 + 2/12?

What is 72/63 + 2/12?

This is how you add

72
63
+
2
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 72 by 12, and get 864, then we multiply 63 by 12 and get 756.

72/63 times 12

Now for the second term. You multiply 2 by 63, and get 126, then multiply 63 by 12 and get 756.

2/12 times 63

This gives us a new problem that looks like so:

864
756
+
126
756

Step 2

Since our denominators match, we can add the numerators.

864 + 126 = 990

So what's the answer so far?

990
756

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:

990
756
÷ 2 =
495
378

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:

495
378
÷ 3 =
165
126

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

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

165
126
÷ 3 =
55
42

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. 43 is larger than 42. So we're done reducing.

And we're done! Here's the final answer to 72/63 + 2/12

72
63
+
2
12
=
55
42
© 2014 Randy Tayler