My 8th graders love this game for a warm-up! It basically works like the game Guess Who, or 20 Questions.
I print copies of the above image and put them in sheet protectors with a dry erase marker for each student. Students take turn asking yes/no questions to try to figure out which number I chose while marking out numbers that it can't be. The first student who correctly guesses my number wins a prize.
This is great for teaching number sense and vocabulary for my tutoring groups. Some example questions the students could ask are:
- Is it even/odd?
- Is it prime/composite?
- Is it a multiple of ...?
- Is it a factor of...?
- Is it less/greater than...?
I am going to make a decimal and fraction version of this as well, and maybe even try the periodic table.