Estimation
Pick the right answer fast — estimate, don't calculate.
Which is correct?
How to play
Each round shows a calculation — a big multiplication, a percentage, or a large sum — with four possible answers. Only one is exactly right; the others are close enough that you can't tell at a glance. The trick is to estimate: round the numbers, get a ballpark, and eliminate the answers that are clearly too big or too small. Tap the one that's left. Solve as many as you can before time runs out.
Estimation shortcuts
- Round to the front digit. 312 × 19 is roughly 300 × 20 = 6,000, so the answer is near 6,000 — not 600 or 60,000.
- Percentages are fractions. 25% is a quarter, 20% is a fifth, 10% just moves the decimal. 24% of 850 ≈ a quarter of 850 ≈ 210.
- Check the last digit. When two options are close, the units digit of a product often rules one out instantly.
- Count the zeros. Getting the order of magnitude right eliminates most wrong answers on its own.
What's a good score?
| Solved in 60s | Level |
|---|---|
| Under 8 | Warming up |
| 8–13 | Good number sense |
| 14–20 | Strong |
| 21+ | Excellent |
Why estimation matters
Being able to estimate is arguably more useful day-to-day than exact calculation. It's how you sanity-check a bill, a spreadsheet total, a news statistic, or a deal that sounds too good. A strong sense of "about how big should this be?" catches errors that exact arithmetic, done on autopilot, sails right past.
Frequently asked questions
Is the Estimation game free?
Yes, completely free and no sign-up. It runs in your browser and your best score is saved on your device.
Am I supposed to calculate the exact answer?
You can, but you usually won't have time. The game is designed so that estimating the size of the answer lets you eliminate the wrong options and pick the right one quickly.
What happens if I pick a wrong answer?
The correct answer flashes briefly and the game moves on. Wrong picks don't count toward your score but they do use up time, so it pays to be both fast and accurate.
Does it work on mobile?
Yes — just tap the answer. It works on phones, tablets and computers.