There are many versions of Gomoku online game. Two players take turns claiming squares and the goal is to get five squares in a row. Rows can be horizontal, vertical, or diagonal.
To use this game to practice number sense, students must claim their number with an equation. For example, when the red player chooses the space 45, he must claim it by telling the other player 9 X 5 = 45. The blue player verifies that this equation is correct.
Students may use any process we have learned in class to claim their number. I have each pair turn in a paper with the two names and a list of the equations they used to play the game.