Desmos is a free graphing and teaching tool for math. In addition to plotting equations, classroom activities are available to help students learn about a variety of math concepts. For example, students can learn how to transform periodic functions by trying to slide marbles through points on a graph. Or, they can plug in their own equation and see what kind of graph pops up; sliders allow students to adjust values and see what happens. Users can also click directly on the graph to find the coordinates of points of intersection, maxima, and minima.
Desmos encourages students to practice math skills as well as play with math to express their creativity. Kids can enter an unlimited number of mathematical expressions and instantly see results graphed on the page. A variety of colors and features make it possible to turn graphs into complex and realistic drawings. With a free Desmos account, students and teachers can save graphs to revisit later.