Percentages When Shopping: Discounts, Tax and Tips

The fastest way to handle shopping percentages is the multiplier: 25% off means multiply by 0.75, adding 20% tax means multiply by 1.2. To remove a percentage that was already added, divide by the multiplier instead of subtracting.

Discounts

25% off 80: $80 \times 0.75 = 60$.

Stacked discounts

30% off, then an extra 10% off, on 120:

That is 37% off in total, not 40%, because the second discount applies to the already-reduced price.

Adding tax

Add 20% VAT to 100: $100 \times 1.2 = 120$.

Removing tax (reverse percentage)

A price of 59.99 includes 20% VAT. The pre-tax price is

Tips

A 15% tip on 86.40: $86.40 \times 0.15 = 12.96$, so the total is 99.36. Split 3 ways, that is 33.12 each.

Mental shortcut: 10% is the bill with the decimal point moved one place left (8.64). 5% is half of that (4.32). Add them for 15%: 12.96.

Quick multiplier table

Common mistakes

• Adding stacked discounts together.
• Subtracting a percentage to remove tax.
• Tipping on the wrong amount (before or after tax: either is fine, just be consistent).

Practice questions

1. 40% off 65?
2. Remove 20% VAT from 96.
3. A 20% tip on 54.50?

Answers: 1) 39 2) 80 3) 10.90

Try the discount calculator, the sales tax and VAT calculator and the tip calculator. The basics are in how to calculate a percentage.

Frequently asked questions

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