### Calculating percent problems

There are many times in real life when you may need to calculate a percentage. You might need to figure out how much money a **5% discount** will save you, or how much interest you'll pay on a loan with a **6% interest rate**. Knowing how to calculate percentages will help you in both of these situations.

#### Setting up the calculation

Let's say the mailing department was responsible for 25% of the accidents at your company this year. There were 80 accidents total, and 20 of them were in the mailing department. You could write that like this:

25% of 80 = 20

This expression tells you that 25% of 80 is equal to 20. But what if you don't know how much a percentage is equal to? Let's say the demolition department was responsible for 50% of the 80 accidents. You don't know how many accidents 50% of 80 is. So you could write that like this:

50% of 80 = ?

To figure out what 50% of 80 is, you'll need to rewrite this example so it can be solved with math.

Click through the slideshow to see how to set up the example as a mathematical expression.

We need to turn this example into something we can solve with math.

First, we'll deal with the word **of**. Whenever you see that word in a percentage problem, it usually means **multiplication**.

First, we'll replace the word **of **with a **multiplication** sign.

Now we need to convert our percentage into a decimal. We'll do that by inserting a decimal point after the 50...

We'll do that by inserting a decimal point after the 50...and moving it two places to the left.

Now we have an equation we can use math to solve. All we have to do is **multiply **0.50 by 80.

Let's set up another example. This time we want to find 7% of 120.

First, we'll replace the word **of **with a multiplication sign.

We'll turn our **percent** into a **decimal**. We'll insert our decimal point after the 7...

We'll turn our **percent** into a **decimal**. We'll insert our decimal point after the 7...and move it two spaces to the left.

Now we've set up an equation we can solve with math.