Here is a tool to faciltate playing Bing- a game where you have to recognize the factors of numbers. Here is an explanation of how to play the game. Tell the kids the factor you want to play say 3. Then go around the room having kids count out starting from 1. Every time a number is called that is a multiply of the factor you started with, the person must say Bing instead of the number. If they don't, they sit down. You can increase the difficulty by adding other factors- say 3 could be Bing, 4 could be Pow, and 5 could be Kaboom. In this game the person who was supposed to say 15 would say Bing and Kaboom. 60 would be Bing, Pow and Kaboom.