math help

What is 9/16 + 9/12?

What is 9/16 + 9/12?

Here's how we add

9
16
+
9
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 9 by 12, and get 108, then we multiply 16 by 12 and get 192.

9/16 times 12

Do the same for the second term. We multiply 9 by 16, and get 144, then multiply 16 by 12 and get 192.

9/12 times 16

The problem now has new fractions to add:

108
192
+
144
192

Step 2

Since our denominators match, we can add the numerators.

108 + 144 = 252

The sum we get is

252
192

Step 3

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

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

252
192
÷ 2 =
126
96

Now, try the same number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

126
96
÷ 2 =
63
48

Now, try the same number again.

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

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

63
48
÷ 3 =
21
16

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...

No good. 17 is larger than 16. So we're done reducing.

Congratulations! Here's your final answer to 9/16 + 9/12

9
16
+
9
12
=
21
16
© 2014 Randy Tayler