math help

What is 72/63 + 7/12?

What is 72/63 + 7/12?

Here's how to add

72
63
+
7
12

Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

Now you 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 7 by 63, and get 441, then multiply 63 by 12 and get 756.

7/12 times 63

The problem now has new fractions to add:

864
756
+
441
756

Step 2

Since our denominators match, we can add the numerators.

864 + 441 = 1305

This yields the answer

1305
756

Step 3

The last step is to reduce the fraction if we can.

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:

1305
756
÷ 3 =
435
252

Now, try the same number again.

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

435
252
÷ 3 =
145
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 + 7/12

72
63
+
7
12
=
145
84
© 2014 Randy Tayler