A Monday afternoon, working with one of my second graders, helping him fill in a blank hundreds grid. Suddenly it hit me. What if... ...using different colored pencils, players alternate capturing squares on a hundreds grid... ...while trying to get 4 squares in a row, column, or diagonal. It would work just like tic-tac-toe. Each tic-tac-toe is worth a point, and you can keep track with tallies. Play until the board is filled up. Theresa and I played a practice round: Initially we tried 3 in a row, but things got very confusing and we decided that 4 in a row was better. We also tried a game where a square could be used in multiple tic-tac-toes, but didn't like that either. We also decided that the 0 and 100 would not count towards any player's tic-tac-toe. And then it was time to take newly christened Number Grid Tic-Tac-Toe for a test drive. (Apologies if someone holds the patent on this!) Jane's class was first, and we decided to get crazy and use a grid that went from 1 to 120. It took only about 5 minutes playing a demo game with a volunteer under the document camera and they were ready to rumble. "Hmmm. Where should I go?" "I think I can figure this out in my head." Playing it safe. Using a number grid to help is so SMP 5. A barn-burner. You can see here that 34 was used twice, as was 46. Over the next several weeks I tried it out with 3 more second grade classes and 1 third grade class. I asked each to write down their reflections and reactions on the back of their game boards. Here's a sample: I liked this game because it was fun to figure out where the numbers go. I like this game because you need strategy. I loved it so much but hard. So hard!!! I think the game helps because to put the right number in the right place you have to count by numbers and learn to do that in the game. I liked it because I outsmarted (my opponent) when he tried to outsmart me. I like this game because you have to think hard. The kids came up with some awesome suggestions for modifying the game, including: If someone gets stuck, the other player gets a point. If you get three in a row you get half a point. Add a few numbers scattered around the board. (Love it! This child wants it differentiated!) If you get five in a row you get 2 points. Jane's class experimented with a 3 player game: They found that 3 in a row was better with 3 players. Maggie's class tried something a little more difficult: "What goes here?" Many possibilities... If it's green's turn, where should he go? Why? Defend your answer. I'm happy to report that the game is wildly popular; for some reason it hits that elusive kid sweet spot. I suspect it's because the cognitive demand is just right. (I like this game because you have to think hard. Unspoken: But not too hard?) And because the kids already know how to play tic-tac-toe, they can expend their mental energy on strategy and on figuring out which number goes in what square without worrying about a bunch of rules. The teachers love it too because it's easy to explain and takes almost no effort to prepare. So grab a blank grid and some colored pencils and have some fun!