Percentage discounts & sale price
Theory
A discount is the amount taken off a price. When an item is \(25\%\) off, the discount is \(25\%\) of the original price, and the sale price is the original price minus the discount. This Year 6 maths page shows how to find discounts and sale prices for \(10\%\), \(25\%\) and \(50\%\) off, how much of the price you still pay, and how to compare offers.
The original price is the price before the sale. The discount is the amount of money taken off.
Sale price = original price − discount.
\(10\%\) off means the discount is one tenth of the price; \(25\%\) off is one quarter; \(50\%\) off is one half.
The percentage you still pay is \(100\%\) minus the discount.
With \(50\%\) off, the discount and the sale price are the same amount.
Discounts and sale prices:
| Discount | You save | You pay |
|---|---|---|
| \(10\%\) off | \(\dfrac{1}{10}\) | \(90\%\) |
| \(25\%\) off | \(\dfrac{1}{4}\) | \(75\%\) |
| \(50\%\) off | \(\dfrac{1}{2}\) | \(50\%\) |
Finding the sale price
- Find the discount: \(10\%\) divide by \(10\), \(25\%\) divide by \(4\), \(50\%\) divide by \(2\).
- Subtract the discount from the original price.
Finding the original price after 50% off
- Double the sale price, because the sale price is half of the original.
(i) What is the discount?
(ii) What is the sale price?
| \(70 \div 10\) | \(=\) | \(7\) |
| \(70 - 7\) | \(=\) | \(63\) |
(i) \(\$7\)
(ii) \(\$63\)
| \(84 \div 4\) | \(=\) | \(21\) |
| \(84 - 21\) | \(=\) | \(63\) |
\(\$63\), as in the first diagram.
| \(66 \div 2\) | \(=\) | \(33\) |
The discount is \(\$33\) and the sale price is also \(\$33\).
| \(45 \div 10\) | \(=\) | \(4.5\) |
| \(45 - 4.5\) | \(=\) | \(40.5\) |
\(\$40.50\).
(i) What percentage of the price do you pay?
(ii) Use it to find the sale price of a \(\$130\) item.
| \(100\% - 20\%\) | \(=\) | \(80\%\) |
| \(130 \div 10 \times 8\) | \(=\) | \(104\) |
(i) \(80\%\)
(ii) \(\$104\)
(i) Find the sale price with \(25\%\) off.
(ii) Find the sale price with \(50\%\) off.
(iii) How much more does the \(50\%\) offer save?
| \(160 - 40\) | \(=\) | \(120\) |
| \(160 - 80\) | \(=\) | \(80\) |
| \(120 - 80\) | \(=\) | \(40\) |
(i) \(\$120\)
(ii) \(\$80\)
(iii) \(\$40\) more
| \(38 \times 2\) | \(=\) | \(76\) |
\(\$76\).
| \(120 \div 4\) | \(=\) | \(30\) |
| \(120 - 30\) | \(=\) | \(90\) |
\(\$30\) is the discount. She must subtract it: the sale price is \(\$90\).
Common pitfalls
Frequently asked questions
What is a discount?
The amount of money taken off the original price.
How do you find the sale price?
Find the discount, then subtract it from the original price.
What percentage do you pay with 50% off?
\(50\%\) of the original price.
Is 50% off the same as half price?
Yes. The discount and the sale price are equal.
How do you find the original price after 50% off?
Double the sale price: \(\$38\) becomes \(\$76\).