(Pat Eaton-Robb/AP)

It’s a simple formula and Virginia will be doing it again this year. The annual sales-tax holiday for school supplies runs from Aug. 5 to 7.

Shoppers can buy, tax free, certain school supplies selling for $20 or less per item and footwear that retails for $100 or less. Retailers can also absorb the taxes on other items but are still responsible for paying the tax to the state.

To see which items qualify for the holiday, see the Virginia Department of Taxation Web site.