We played a math game today called Bats In A Cave.
Our Engage NY curriculum suggested playing a similar game with bears and individual tubs, but we changed it up a bit. Our focus was on "Conservation of Number" where kids develop an understanding that if they started with 5 and put 2 on top, there would still be 5 all together... we just moved them around a bit. It's the same idea as having 20 objects all in a line and then messing them all up. There are still 20 objects there, but the five year old brain doesn't realize that.
There are full directions for playing the Bats In A Cave Addition game on the LeapFrog Learning Path Website if you are interested. The game we played in class was specifically focused on Conservation of number, while the game on the LeapFrog website has more of an addition/subtraction focus. It a really simple and fun way to work on number fluency with your kids at home!