I used Wolfram Mathematica to teach a lesson on vector fields and Lotka-Volterra equations. Mathematica is a computing software that can be used to calculate and graph complex equations such as two-dimensional and three-dimensional vector fields. Mathematica is a very useful tool in the classroom because it can be used to visualize complex equations. Mathematica also allows you to easily solve problems such as matrix multiplication and problems in fields such as computing and engineering. Mathematica can be purchased and downloaded here.