IKNOW is a game I borrowed from Math in the Middle. I like it because it’s simple and involves all students. It’s the same idea as Bingo, but much easier. Print blank IKNOW grid sheets. Students number their grid from 1 -24 with the free space in the middle. Show a problem on the board, give time for students to solve it, have students show what they “Know,” call out a number from 1-24. Students who got the problem right get to place a marker on their IKNOW board. When they get a “bingo” they shout “I Know!”