math help

What is 4/40 + 5/12?

What is 4/40 + 5/12?

Here's how you add

4
40
+
5
12

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 4 by 12, and get 48, then we multiply 40 by 12 and get 480.

4/40 times 12

Now for the second term. You multiply 5 by 40, and get 200, then multiply 40 by 12 and get 480.

5/12 times 40

This gives us a new problem that looks like so:

48
480
+
200
480

Step 2

Since our denominators match, we can add the numerators.

48 + 200 = 248

So what's the answer so far?

248
480

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

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

248
480
÷ 2 =
124
240

Now, try the same number again.

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

124
240
÷ 2 =
62
120

Now, try the same number again.

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

62
120
÷ 2 =
31
60

Now, try the same number again.

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

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 31. So we're done reducing.

Congratulations! Here's your final answer to 4/40 + 5/12

4
40
+
5
12
=
31
60
© 2014 Randy Tayler