How do you calculate the sales tax on a purchase?

1. Sales tax is a percent of the purchase price. 2. To find an amount that is a percent of another amount, that percent, changed to a decimal, is multiplied by the amount. 3. So the sales tax is found by multiplying the purchase price by the tax rate. 4. Adding, dividing, or subtracting the tax rate do not correctly apply a percentage to the purchase price. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 6 "Percents", section 6.3 Solve Sales Tax, Commission, and Discount Applications_