math help

What is 3/4 + 9/12?

What is 3/4 + 9/12?

Here's how to add

3
4
+
9
12

Step 1

Our denominators (bottom numbers) don't match, so we can't add yet.

Since 4 is evenly divided by 12, we can multiply just one term to get a common denominator.

Multiply 3 by 3, and get 9, then we multiply 4 by 3 and get 12.

So now our fractions look like this:

9
12
+
9
12

Step 2

Since our denominators match, we can add the numerators.

9 + 9 = 18

Now we have an answer.

18
12

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...

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

18
12
÷ 2 =
9
6

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:

9
6
÷ 3 =
3
2

Now, try the same number again.

No good. 3 is larger than 2. So we're done reducing.

Congratulations! Here's your final answer to 3/4 + 9/12

3
4
+
9
12
=
3
2
© 2014 Randy Tayler