Number sense is something most students need to work on... I like this game because it reviews place value, odd/even numbers, and other basic vocabulary without the students realizing their speaking math.
The game is played as a whole group. One person, the person "in charge", writes a number on a slip of paper. The teacher will hold the paper. The person "in charge" will stand at the board. He/she can ONLY answer yes or no questions. The other students in the classroom try to guess the number. The class can ask...
Blog Post: http://www.dowegetagradeforthis.com/number-sense-guess-the-number/