How the game works
A number flashes on screen, then hides. Type it back. Get it right and the next number is one digit longer. The game starts with a single digit and ends the first time your answer is wrong. Your score is the longest number you got right, and most adults reach 7 to 8 digits.
It is free, needs no account and saves your scores in the browser.
Challenge rules for friends or a classroom
The game is solo by design, but a few house rules turn it into a contest.
- Best of three. Everyone plays three runs and keeps their highest score. This smooths out an unlucky slip.
- Pass and play. Share one device. Each player takes one run, and the longest number wins the round.
- Team total. Split into teams and add up every member’s score. This suits a classroom because each student’s run counts.
- Silent round. No saying the digits out loud and no writing them down. Then play a normal round and see how much rehearsal helps.
- Beat your own line. Each player tries to top their own previous best, so beginners and strong players compete on improvement.
Agree on the rules before the first number appears, and have players call out their score as soon as a run ends.
Tricks to go further
Chunk the digits. Read 471936 as 471, 936. Six items become two. Working memory seems to hold about four chunks, so the fewer pieces you make, the further you go.
Use a rhythm. Say the chunks silently with a beat, the way people read out phone numbers with pauses.
Give chunks a meaning. A year, a price, a house number. A chunk that reminds you of something is harder to lose.
Spend the display time well. Read the number once in chunks, then keep repeating the chunks until it hides. Do not start again from the first digit.
Keep it a game
A single score says very little about intelligence, and it moves with sleep and distraction. What makes the game fun is watching your own line climb. Your runs are listed on the dashboard. The full rating table is on the number memory test page, and the short term memory test page explains the science of digit span.