Reading a discount correctly
A percentage discount always applies to the original price, not to any price that's already been reduced — which matters when a sale is stacked ("25% off, plus an extra 10%"). Two sequential discounts don't add together; 25% off followed by 10% off the new price works out to about 32.5% off the original, not 35%. When in doubt, calculate each step separately rather than adding the percentages.