1. Percent of Change percent of increase percent of decrease
A percent of change indicates how much a quantity increases or decreases with respect to the original amount.
The percent of change is the ratio of the amount of increase or decrease to the original amount.
It’s very similar to the proportion The “part” is the change. The “whole” is the original amount.
The change may be more or less than the original amount.
If the new amount is greater than the original amount, the percent of change is called a _______________________.
If the new amount is less than the original amount, the percent of change is called a __________________________.
For example, let’s say someone originally earned a wage of $25 per hour, then gets a raise and now earns $30 per hour. To find the percent of increase, you first have to find the amount of the change. You don’t actually use the $30 in the proportion itself. You subtract $25 from $30 to get a “change of $5.” Then you set up the proportion:
 Then solve. (One in disguise/Cross-products)
The percent of change is 20%. Since the wage increased, we can say the “percent of increase was 20%.”
percent of increase
percent of decrease

2. 1. Find the percent increase from 150 to 189.
Find the percent decrease from 512 to 320.
The High-Tech Math Store is having a sale on all their calculators. The original cost of a graphing calculator was $ It is on sale for $ What is the percent of discount?
The original amount:
The NEW amount:
Find the percent of increase or decrease.
Sydney bought a pair of shoes that were on sale. She paid $90 (not including tax). If she had purchased the shoes while they were NOT on sale, she would have paid $110 (not including tax). What was the percent discount she received?
THINKER! Last summer John hit 25 home runs. If he increases this number by 20% next year, how many home runs can he expect to hit?