Sales tax is an additional amount of money that you pay for having purchased something. The way this is calculated is by having your 6% converted into a fraction. A percent is 1/100, so 6 percent is 6/100. You multiply the 6/100 times the price of the product that your buying; in this case, it is a jacket. The number you get is then added to the initial cost of the jacket because you need to pay for the jacket and the sales tax.