Balloon

Every pump banks a dollar until the balloon pops. How many pumps do you plan? As many as you can in 60 seconds, each one scored the moment you answer.

How it works

1. Each round says how the balloon pops. Plan how many pumps to try: each one that doesn't pop it banks $1, and a pop loses the round's money.
2. You score your plan, not your luck: the expected money from your number of pumps against the best number. 10, 5 or 2 points, judged more strictly as you improve.
3. Rounds get harder as you improve: from evenly random pops to a chance on every pump, balloons that can't pop early, and a mix of weak and strong.

It trains pushing your luck: when to stop. After every round you see the best answer and why.

Play balloon

Play with friends or a club

Challenge a friend with a duel link, or run a tournament for a club or class: one link, the same rounds for everyone, one run each, and a live leaderboard.

Also try Sixty-second math, or the probability puzzles.