Percent of Change

How much did a gallon of milk cost in the 1950’s? What happens when you keep sharpening your pencil? What if you get a raise in your allowance?

Percent of Change: Compares the amount of change to the ORIGINAL amount!

Percent of Increase: An increase from the ORIGINAL amount Ex) The cost of milk in the 1950’s compared to today’s cost.

Percent of Decrease: A decrease from the ORIGINAL amount Ex) What happens to your pencil when you keep sharpening it?

Amount of Change = The difference between the ORIGINAL amount and the NEW amount. Life expectancy in 1900 was 45 years old; Life expectancy in 2012 is 78 years old. What is the amount of change? 78 – 45 = 33

Percent of Change Proportion: SUBTRACT!!! Amount of Change % --------------------------- = ------------------------- 100 ORIGINAL Amount 78 – 45 = 33

Steps for Finding Percent of Change: Determine whether the amount is INCREASING or DECREASING from the ORIGINAL amount.

Steps for Finding Percent of Change: 2. Find the amount of CHANGE. SUBTRACT!!! 3. Set-up the Percent Proportion. % Amount of Change --------------------------- = ------------------------- 100 Original Amount

Example 1: An 8 ft. tree grows to be 10 ft. tall in the last year. What is the tree’s percent of change? Increase or Decrease? 25 2 ft % Amount of Change --------------------------- = ------------------------- 100 8 ft Original Amount

Example 2: A pair of jeans was originally priced at $40, but is on sale for $36. What is the percent of change? Increase or Decrease? $4 10 % Amount of Change --------------------------- = ------------------------- 100 $40 Original Amount