# Question

When should I implement the two different percent increase strategies? When should I use the formula of taking the differences between the two numbers, then dividing by the original. And when should I take a number and divide by the other number to see the percent increase (as in this example).

# Answer

It all comes down to the wording of these problems, which can be admittedly confusing. There are a lot of different ways to word the questions, but we can break them down into two categories:

**Category 1**

The original amount is *contained* in the result: look for the phrase "is what percent **of**". Here, you simply use new/old * 100

Example:

Car sales increased from 500 in July to 600 in August. August car sales are what percent of July car sales? 600/500 * 100 = 120%

The second category is probably a bit more common.

**Category 2**

Comparing the difference to the original: look for the phrase "is what percent greater/less than". Here, use the formula (new-old)/old * 100

Example:

Car sales increased from 500 in July to 600 in August. August car sales are what percent greater than July car sales? (600-500)/500 * 100 = 20%

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