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Binary Number Guess

Flip bit cards from 128 down to 1 to make a number, or read the number from the face-up cards. Three levels and a 60-second timer.

How computers count

Computers only know two states: on and off, or 1 and 0. Every number is stored as a row of bits. The rightmost card is worth 1, then 2, 4, 8 and so on, always doubling. To write 13, turn up the 8, 4 and 1 cards because 8 + 4 + 1 = 13, so its binary is 1101. With 8 cards you can make any number from 0 to 255, which is one byte. To convert bigger numbers, try the Number Base tool.

tags: #binary numbers #bits #counting #computer science

time 60scorrect 0 · best 0

0000

Each card is worth double the card on its right: 1, 2, 4, 8, 16, … A face-up card means 1, face-down means 0. Add the face-up cards to get the number. That is how computers store numbers!

Keyboard: digits 1–8 flip cards from the right, 1–4 pick an answer in read mode.

How to install the app

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Android (Chrome)
Tap the ⋮ menu at the top right, then choose "Install app" or "Add to Home screen".
iPhone / iPad (Safari)
Tap the Share button (the square with an up arrow), then choose "Add to Home Screen". On iOS this only works in Safari.
Computer (Chrome / Edge)
Click the install icon (a monitor with a down arrow) at the right end of the address bar, or menu ⋮ → "Install Daily Apps".