math help

What is 25/9 + 9/12?

What is 25/9 + 9/12?

This is how to add

25
9
+
9
12

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 25 by 12, and get 300, then we multiply 9 by 12 and get 108.

25/9 times 12

Now for the second term. You multiply 9 by 9, and get 81, then multiply 9 by 12 and get 108.

9/12 times 9

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

300
108
+
81
108

Step 2

Since our denominators match, we can add the numerators.

300 + 81 = 381

That gives us the sum, which is

381
108

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide 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:

381
108
÷ 3 =
127
36

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...

No good. 37 is larger than 36. So we're done reducing.

Congratulations! Here's your final answer to 25/9 + 9/12

25
9
+
9
12
=
127
36
© 2014 Randy Tayler