Five cards with 1, 2, 4, 8 and 16 dots are enough to count from 0 to 31 and to write a word. Students choose which cards to turn face up on their phones, meet the carry from fifteen to sixteen, and decode a message written in the same cards, while the screen counts what the room did.
A practice run with fictional students. No real classroom or join code is created.
Try an answer on the phone. Lead the lesson from the screen.
On their phone
You are presenting
Setting up the room…
Four cards show 1, 2, 4 and 8 dots, and the fifth is face down. The room guesses its dots, chooses which cards to turn face up to show eleven, then sixteen starting from fifteen, and reads a three-letter word written in the same five cards. The screen counts the guesses, how many turned each card face up and what the room read, never whose. Each wrong reading of the word is another real word, so the counts show how the room misread it.
Up to 600 people
Binary numbersPlace value
Every activity here ships with Decka — sign up free and add any of them to your library from the built-in classroom catalog.
How it works
Sign up free and pull the activity from Decka's built-in classroom catalog — one click copies it into your own library, ready to run from Decka or inside PowerPoint.
Everyone scans from the projector and plays in their phone's browser. No app, no account, nothing to install.
You move the activity phase by phase: collection closes, the boards resolve on the big screen, and the debrief happens while the results are still up.
Start free. No credit card required.
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