math help

What is 72/63 + 8/11?

What is 72/63 + 8/11?

Here's how to add

72
63
+
8
11

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 11, and get 792, then we multiply 63 by 11 and get 693.

72/63 times 11

Do the same for the second term. We multiply 8 by 63, and get 504, then multiply 63 by 11 and get 693.

8/11 times 63

The problem now has new fractions to add:

792
693
+
504
693

Step 2

Since our denominators match, we can add the numerators.

792 + 504 = 1296

This yields the answer

1296
693

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:

1296
693
÷ 3 =
432
231

Now, try the same number again.

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

432
231
÷ 3 =
144
77

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...

No good. 79 is larger than 77. So we're done reducing.

Congratulations! Here's your final answer to 72/63 + 8/11

72
63
+
8
11
=
144
77
© 2014 Randy Tayler