How to Do Sales Tax in Math

The amount of sales tax you pay on an item differs between states. Some states, such as New Hampshire and Texas, do not have a state sales tax, but most states do. Sales tax is referred to by percentage. The amount of tax you pay depends on the total amount of your purchase. The tax you pay is then sent to your state government for state expenses. Calculating the amount of sales tax you owe involves relatively simple mathematical calculations.

• 1

  Convert the percentage to a decimal by moving the decimal point two places to the left. If the sales tax is 6 percent, move the decimal two places to the left to get .06.

• 2

  Multiple the decimal by the total purchase price. If you purchase a pair of jeans for $29.99, multiple the price (29.99) by .06 to get 1.7994.

• 3

  Round this number up to the nearest cent. In this case the amount of sales tax you owe is $1.80 because 1.7994. rounds up to 1.80.

• 4

  Calculate the total amount owed by adding $1.80 to the original price. In this example, adding $1.80 to $29.99 results in a total cost of $31.79 to purchase the jeans.