The goal of this game is to simplify linear expressions.  You will be given a linear expression, two possibilities for the first step, and two possible results after performing the first step.  Identify the correct first step and correct result and note the shape key (triangle, circle, square, and pentagon).  First click on the shooter once.  Then use your "LEFT" and "Right" arrow keys to aim the shooter and use the "UP" arrow key to fire.  You will want to hit the shapes so that the two correct shapes collide into each other.  The two first step shapes will bounce off each other as will the two result shapes.  Hitting the center square can produce unpredictable results.  If there is more than one step to a problem, you will need to succeed multiple times before advancing a level.  If there is no match after 28 seconds, the game will time out you you can try that step again.  Good luck!