math help

What is 4/40 + 1/12?

What is 4/40 + 1/12?

Let's add

4
40
+
1
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 1 by 40, and get 40, then multiply 40 by 12 and get 480.

1/12 times 40

This gives us a new problem that looks like so:

48
480
+
40
480

Step 2

Since our denominators match, we can add the numerators.

48 + 40 = 88

That gives us an answer of

88
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:

88
480
÷ 2 =
44
240

Let's try dividing by that again...

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

44
240
÷ 2 =
22
120

Let's try dividing by that again...

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

22
120
÷ 2 =
11
60

Let's try dividing by that again...

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

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...

No good. 13 is larger than 11. So we're done reducing.

There you have it! Here's the final answer to 4/40 + 1/12

4
40
+
1
12
=
11
60
© 2014 Randy Tayler