math help

What is 3/18 + 4/11?

What is 3/18 + 4/11?

Let's add

3
18
+
4
11

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 3 by 11, and get 33, then we multiply 18 by 11 and get 198.

3/18 times 11

Do the same for the second term. We multiply 4 by 18, and get 72, then multiply 18 by 11 and get 198.

4/11 times 18

So now our fractions look like this:

33
198
+
72
198

Step 2

Since our denominators match, we can add the numerators.

33 + 72 = 105

Now we have an answer.

105
198

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...

Nope! So now we try the next greatest prime number, 3...

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

105
198
÷ 3 =
35
66

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

No good. 37 is larger than 35. So we're done reducing.

There you have it! Here's the final answer to 3/18 + 4/11

3
18
+
4
11
=
35
66
© 2014 Randy Tayler