In a room of 30 kids, what are the odds two of them share a birthday?
Open for the projector Present it step by step
Classroom mode
A question for the whole room
One story to open. A room full of ideas to test.
Ready in three steps
- Open the story.Read and try the first pages together.
- Pause for a prediction.At the story’s question, read its choices aloud. Invite a vote and ask, “What makes you think that?”
- Run it. Watch. Wonder.Choose the class’s prediction, run the experiment, and compare what happened with your guesses.
Different guesses are welcome. The experiment gives everyone something to rethink.
Something to put on paper
A one-page prediction and observation sheet. No answers included.
After the experiment: discussion notes
Talk about what happened
- Predict first: by a 30-person room, which question has crossed one-half—or has neither?
- Why does the chosen-person model add one spoke while the all-pair model adds several links?
- How would fewer possible dates change the no-match calculation?
Where it shows up in real life
- A classroom or sports team comparing one person's birthday with every pair
- A party where people discover a birthday twin without planning it
- Matching first initials, favorite colors, or other labels inside a group
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