Each lock is a 'how many ways?' puzzle. Count the possibilities correctly to crack it, guess wrong and the alarm costs you ten seconds.
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How to play
Work down a vault of combinatorics locks, each asking how many ways something can happen. Pick the right count from the options to open the lock and move on. Wrong picks add a time penalty and briefly lock you out, so accuracy beats guessing. Crack the whole vault as fast as you can.
Use permutations when order matters and combinations when it doesn't.
Independent choices multiply together.
Score rewards speed and few misfires; a solutions recap explains every lock.
Controls
Desktop: click the answer you believe is the correct count.
Phone & tablet: tap your answer, fully touch-friendly.
Game modes
Daily: one shared vault seeded by the date.
Practice: a fresh randomized vault each run.
Tips & strategy
Decide first whether order matters, that picks permutation versus combination.
Break a lock into independent stages and multiply their counts.
What you'll learn
Counting Cards is a combinatorics puzzle that drills permutations, combinations and the multiplication principle.
Skills: combinatorics, permutations and combinations, the multiplication principle
Best for: roughly grades 9–12 (ages 14+)
For parents & teachers: counting the ways things can happen.
About Counting Cards
Counting Cards is a timed combinatorics puzzle that drills permutations, combinations and the multiplication principle. It's an original free browser game made for PlayPendium.
A free, original browser game on PlayPendium. No download, no install.
