Counting Cards

Each lock is a 'how many ways?' puzzle. Count the possibilities correctly to crack it — guess wrong and the alarm costs you ten seconds.

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. Browse all games →