One student is the “Number Detective”. Another student picks a secret number between 1 and 100 without saying. The detective has 10 chances to guess the number by asking yes/no questions like:

• "Is it more than 50?"
• "Is it less than 30?"
• "Is it an even number?"
• "Is it between 10 and 20?"
• "Does it end with a 5?"
• "Is it a multiple of 10?"

After the questions, the detective makes a guess:
“I think the number is 45!”
Players switch, and a new student becomes the detective.