math help

What is 72/63 + 6/12?

What is 72/63 + 6/12?

This is how to add

72
63
+
6
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 6 by 63, and get 378, then multiply 63 by 12 and get 756.

6/12 times 63

This gives us a new problem that looks like so:

864
756
+
378
756

Step 2

Since our denominators match, we can add the numerators.

864 + 378 = 1242

That gives us an answer of

1242
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:

1242
756
÷ 2 =
621
378

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

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

621
378
÷ 3 =
207
126

Let's try dividing by that again...

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

207
126
÷ 3 =
69
42

Let's try dividing by that again...

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

69
42
÷ 3 =
23
14

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

No good. 17 is larger than 14. So we're done reducing.

There you have it! Here's the final answer to 72/63 + 6/12

72
63
+
6
12
=
23
14
© 2014 Randy Tayler