Module 2: Percent Problems Tool Kit

Key vocabulary terms, definitions, and proportions for solving percent problems including percent of increase, percent of decrease, sales tax, tips, mark-ups, discounts, and percent error.

Percent of Increase

The percent a value increases when the original amount increases, found by calculating the difference between amounts and setting up the proportion $\frac{\text{the difference between amounts}}{\text{original amount}} = \frac{\text{percent}}{100}$.

Percent of Decrease

The percent a value decreases when the original amount decreases, found by calculating the change in the amounts and completing the proportion.

Sales Tax

A state or local tax that is added to the price of an item or service.

Tip

An additional amount of money paid in return for a service, added to the bill to find the total cost.

Mark-up

An amount added to the wholesale cost by a store to make a profit off the merchandise, calculated using $\frac{\text{amount of mark-up}}{\text{original amount (wholesale cost)}} = \frac{\text{percent}}{100}$.

Wholesale Cost

The original amount paid for merchandise before a mark-up is added.

Discount

The amount by which the regular price of an item is reduced, which is subtracted from the original amount to determine the sale price.

Percent Error

The percent that compares the amount of error to the actual amount, calculated using the proportion $\frac{\text{amount of error}}{\text{actual amount}} = \frac{\text{percent}}{100}$.

Discount Proportion

The mathematical proportion used to calculate a discount: $\frac{\text{discount price}}{\text{original amount}} = \frac{\text{percent}}{100}$.