How Do You Calculate a Discount?
Multiply original price by discount %, divide by 100, subtract from original price. Example: 25% off $79.99 → $79.99 × 25/100 = $20.00 → $79.99 − $20.00 = $59.99.
For double discounts: apply the first discount to get an intermediate price, then apply the second discount to that. 20% + 10% off $100: first $100 → $80, then $80 → $72. The effective discount is 28%, not 30%.