The CMP, an investigation based, games and inquiry styled math curriculum has been well received by the kids who think it is cool to play games, make charts and learn math.
The first cool activity have was the Factor Game where player one circles a number on a board of 1-30 and player 2 in turn circles it's proper factors and they both score the respective points. Already circled numbers can't be circled again. A player shouldn't circle a number where the opponent is unable to score a single point, if that's not possible the game ends. The aim being to score the highest points.
We played the Factor Game many times as the kids started to realize various strategies to win and wanted to try them out.
It was followed by a complete investigation on the best and worst first moves, where they noticed the best first move were numbers which had no factors except 1 and that these were prime numbers and the composite with most factors to be the worst.
Ok that was 30, what about 40, a 100 game board! They could stretch and strategize Masha Allah.
Observations had to be made as to how can one be sure we've covered all the factors for a number, any interesting patterns to be seen.. and lo and behold the kids who felt they were bad at math were the ones discovering patterns now and realized they were actually good at it. There are alternately more and less factors chimed one.
And Odd numbers have a maximum of upto 3 proper factors only, the others took forward the observation.