math help

What is 72/63 + 1/12?

What is 72/63 + 1/12?

Let's add

72
63
+
1
12

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

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

72/63 times 12

Do the same for the second term. We multiply 1 by 63, and get 63, then multiply 63 by 12 and get 756.

1/12 times 63

So now our fractions look like this:

864
756
+
63
756

Step 2

Since our denominators match, we can add the numerators.

864 + 63 = 927

Now we have an answer.

927
756

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

Nope. Try the next prime number, 3...

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

927
756
÷ 3 =
309
252

Now, try the same number again.

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

309
252
÷ 3 =
103
84

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

Nope. Try the next prime number, 67...

Nope. Try the next prime number, 71...

Nope. Try the next prime number, 73...

Nope. Try the next prime number, 79...

Nope. Try the next prime number, 83...

Nope. Try the next prime number, 89...

No good. 89 is larger than 84. So we're done reducing.

Congratulations! Here's your final answer to 72/63 + 1/12

72
63
+
1
12
=
103
84
© 2014 Randy Tayler