Question 1

How do I calculate a discount percentage?

Accepted Answer

To calculate the final price after a discount: Final Price = Original Price × (1 - Discount% / 100). For example, $80 with 25% off: $80 × 0.75 = $60. To find savings: Original Price × (Discount% / 100).

Question 2

How do I figure out the original price from a sale price?

Accepted Answer

If you know the sale price and discount percentage: Original Price = Sale Price / (1 - Discount% / 100). For example, if something is $60 after 25% off: $60 / 0.75 = $80 original price.

Question 3

Which is better: 25% off or $20 off?

Accepted Answer

It depends on the original price. For a $100 item, 25% off saves $25 (better than $20 off). For a $60 item, $20 off is better than 25% ($15). Calculate both to compare: if Original × 0.25 > $20, the percentage is better.

Question 4

How do I calculate stacked discounts (multiple discounts)?

Accepted Answer

Apply discounts sequentially, not by adding percentages. For 20% off then additional 10% off: First apply 20% (×0.80), then 10% to that result (×0.90). Total: 0.80 × 0.90 = 0.72, or 28% off total - not 30%.

Question 5

How do I quickly calculate common discounts in my head?

Accepted Answer

50% off: divide by 2. 25% off: divide by 4 and subtract. 20% off: divide by 5 and subtract. 10% off: move decimal left and subtract. For example, 20% off $45: $45/5 = $9 off, so $36 final price.