Quick Percent is a free daily mental math game. Each day brings ten percentage questions of the kind you meet at work: a discount, a tax on top, a growth rate, the price before a discount. Work each one out in your head and tap the right answer out of four. The clock runs, and a wrong tap adds 5 seconds. Monday stays with 10%, 20%, 25% and 50%. Friday asks you to work backwards from a discounted price.
No sign-up and nothing to install. It runs in your browser on a computer or a phone, and your progress is saved on your device.
- Ten questions, one clock. The clock starts when you tap Start and stops after the tenth right answer.
- Whole numbers only. No decimals and no currency, so the sums are the same in every country.
- Mistakes cost time. A wrong answer is crossed out and adds 5 seconds. You then try again.
- Stuck? The lightbulb removes two wrong answers from the question on screen.
How to play Quick Percent
- Tap Start. The first question appears and the clock begins.
- Read the question and work it out in your head.
- Tap the right answer. On a keyboard you can press 1, 2, 3 or 4.
- After the tenth right answer the clock stops. You then see all ten questions with their answers.
The seven kinds of question
| Kind | Example | One way to think | First appears |
|---|---|---|---|
| A share | What is 25% of 80? | 25% is a quarter. 80 ÷ 4 = 20. | Monday |
| Discount | 80 with 25% off | Take the share away: 80 − 20 = 60. | Monday |
| Tax | 80 plus 10% tax | Add the share: 80 + 8 = 88. | Tuesday |
| What percent? | 12 is what percent of 48? | 12 goes into 48 four times, so it is a quarter: 25%. | Wednesday |
| Change | From 40 to 50 | The change is 10. Compare it with the start: 10 out of 40 is +25%. | Thursday |
| Before the discount | After 20% off, the price is 64 | 64 is 80% of the old price. 64 ÷ 80 × 100 = 80. | Friday |
| Before tax | With 25% tax, the total is 100 | 100 is 125% of the price. 100 ÷ 125 × 100 = 80. | Friday |
Tips for percentages in your head
- Start from 10%. 10% of 240 is 24. Then 5% is half of that, 20% is double, and 15% is 10% plus 5%.
- Use halves and quarters. 50% is a half, 25% is a half of a half, and 75% is a half plus a quarter.
- Turn a discount around. 30% off leaves 70%. It is often quicker to work out 70% at once.
- Measure a change from the start. From 40 to 50 is +25%, but from 50 to 40 is −20%, because the starting number is different.
- Estimate before you calculate. Often one or two of the four answers are far too big or too small. Cross them out in your mind first.
How the week gets harder
| Day | Kinds of question | Percentages |
|---|---|---|
| Monday | A share, discount | 10%, 20%, 25%, 50% |
| Tuesday | A share, discount, tax | Also 5% and 75% |
| Wednesday | Also “what percent?” | Also 15%, 30%, 40%, 60% |
| Thursday | Also change, up or down | Also 35%, 45%, 70%, 80% |
| Friday | Also the price before a discount and before tax | Also 55%, 65%, 85% |
Saturday plays like a Wednesday and Sunday like a Tuesday.
Frequently asked questions
Is Quick Percent free?
Yes. There is no account, no download and no paywall.
How is the time counted?
From the moment you tap Start to the tenth right answer. Every wrong answer adds 5 seconds.
Does everyone get the same questions?
Yes. The ten questions are made from the date, so everyone who plays that day gets the same round.
May I use a calculator?
Nobody checks, but the game is meant as mental arithmetic, and estimating is usually faster than typing.
Why is there no currency?
The numbers are plain so that the questions read the same in every country.
When does the new round appear?
At midnight in your local time.
Can I play earlier rounds?
Yes. Open the calendar button at the top of the game and pick any day from the past eight weeks.
Does it work on a phone?
Yes. The four answers are large buttons.
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