Estimation challenges
Estimation is the skill of being usefully approximately right in a few seconds. It catches errors, sizes problems and lets you argue with a number instead of accepting it.
What you'll learn
10 chapters, then the quiz
- 01Why estimateCatching what precision hides.
- 02Anchors worth knowingNumbers to measure against.
- 03Fermi estimatesBreaking the unguessable into the guessable.
- 04Rounding wellSimplify without drifting.
- 05Sanity checksTesting an answer you already have.
- 06Estimating percentagesDiscounts, tips and growth.
- 07Estimating timeThe forecast everyone gets wrong.
- 08Making big numbers realMillions, billions and trillions.
- 09Where estimates go wrongBias, not arithmetic.
- 10Getting betterGuess, then check.
More math & logic tests
See all →- Easy
Mental math sprint
Arithmetic you should be able to do without reaching for a calculator.
8 questions5 min - Hard
Logic puzzles
Short problems where the obvious answer is usually the wrong one.
7 questions9 min - Medium
Probability basics
Coins, dice and cards, plus the traps that come with them.
7 questions7 min