math help

What is 72/63 + 2/6?

What is 72/63 + 2/6?

This is how we add

72
63
+
2
6

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 72 by 6, and get 432, then we multiply 63 by 6 and get 378.

72/63 times 6

Now for the second term. You multiply 2 by 63, and get 126, then multiply 63 by 6 and get 378.

2/6 times 63

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

432
378
+
126
378

Step 2

Since our denominators match, we can add the numerators.

432 + 126 = 558

That gives us the sum, which is

558
378

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:

558
378
÷ 2 =
279
189

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:

279
189
÷ 3 =
93
63

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:

93
63
÷ 3 =
31
21

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. 23 is larger than 21. So we're done reducing.

And we're done! Here's the final answer to 72/63 + 2/6

72
63
+
2
6
=
31
21
© 2014 Randy Tayler