How it works
The wheel lands on a percentage of a number, and you choose the answer, in your head if you can.
Your score and your run
Every right answer adds to the Score, and the run counts how many you got right in a row. Best run remembers your record on this device.
Pick the topics
Start with Easy: half and a tenth are the two you use most in real life. The rest build on them.
Easier or harder
Under Quiz settings choose how many Answers to choose from, and switch on Take the ones I got right off the wheel to work through the whole set until nothing is left.
Shortcuts
- 10%: move the decimal point one place. 10% of 70 is 7.
- 5%: half of 10%.
- 25%: half of a half.
- 75%: take away a quarter.
- 15%: 10% plus half of that.
These work for tips, discounts and sale prices too.
Kept on your device
Everything runs in your browser: no app, no account, nothing sent anywhere. What you change is still here the next time you open the page on this device.