**Percent increase**is when you find a given percent of an amount and then add it to it.

**Percent decrease**is when you find a given percent of an amount and subtract it from it.

One really important thing to remember about percent increase and decrease is that

**percent is always based on something**, it doesn't stand alone, there is always something that it is "of" and with percent increase and decrease problems that is always the ORIGINAL amount.

There are

**three kind**of percent increase and decrease problems and a good first step towards solving a problem is to decide which of them it is:

1.Original amount, percent known, you want to find the new amount.

*If cost of life is running at 3%, how much would you need to live a year if your current expenditure is $920 per month?*

2.Original amount known, new amount known, you want to find out what percent the increase or decrease is.

*The value of Spain exports to Germany increased from €1480 million in 1987 to €2768 million in 1988. What was the percentage increase?*

3.New amount known, percent known, you want to find the original amount.

*An item originally costing $20 is on a 10% off sale. What is the sale price?*

Solve the problems in a paper and write the answer as a comment.

See more information and examples here and here.

ALICIA