Percentages are the one piece of school maths that turns up at work every single day, in promotions, in targets and on your own payslip. You do not need the theory. You need two tricks that work on any number, in your head, in front of a customer.
Trick one: 10% is just moving the point. 10% of R240 is R24. 10% of R89,90 is R8,99. Move the comma one place to the left and you are done.
Trick two: build everything else out of 10% and 5%. 5% is half of 10%. So:
- 20% is two lots of 10%
- 15% is 10% plus half of it
- 25% is two lots of 10% plus a 5%
Take 15% off R240. 10% is R24. Half of that is R12. So 15% is R36, and the price is R204.
Off, versus on. A discount comes off the price. A markup goes on the cost. They use the same arithmetic in opposite directions, and mixing them up is the most common mistake in a stockroom.
A target is the same trick backwards. If you have sold R8 000 against a R10 000 target, you are at 80%, because R1 000 is 10% and you have eight of them. Learning to see how many tenths you have is faster than any formula.
One thing to know rather than calculate: VAT is already included in the shelf price in South African shops, so the price on the label is what the customer pays.
A R450 jacket is marked 30% off. A customer asks what they will pay.
What happens: You will get there, but slowly, and this is exactly the moment a supervisor is watching. It is also the kind of question that comes twenty times on a promotion day.
What happens: Three small steps, all in your head, done before they finish asking. This is the whole method: find 10%, multiply it, subtract.
What about awkward ones like 17,5%?
Break it the same way: 10%, plus 5% which is half of that, plus 2,5% which is half again. For anything genuinely awkward, use the calculator without embarrassment. The tricks are for the common ones, and the common ones are 10, 15, 20, 25 and 50.
Buy two get one free, what percentage is that?
You pay for two and take three, so you are paying two thirds of the full price, which is a discount of about 33%. Useful to know when a customer asks whether it is better than the 30% off next to it. It is, slightly, but only if they wanted three.
How do I check a discount the till applied?
Do the rough version in your head and compare. If the till took R200 off a R450 jacket marked 30% off, that is wrong, because 30% of R450 is R135. Tills apply the promotion they were programmed with, which is not always the promotion on the poster.
Before you move on
- Practise moving the comma to find 10% of any price
- Build 15, 20 and 25 percent out of 10 and 5
- Check a till discount against your own rough figure
Check what you know
4 questions. Have a look at what this lesson asks.
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