This interactive Java applet, based on the familiar game Connect Four, gives students practice in applying order of operations. Two players take turns evaluating expressions involving the four basic operations (addition, subtraction, multiplication and division). If correct, the player places a black or red checker on the board with the goal of connecting four in a row ( horizontally, vertically, or diagonally) before the opponent does. Players choose from four levels of difficulty; they can adjust the timing feature and whether to involve exponents and/or parentheses.