With Desmos you can draw graphs, points and tables in a two-dimensional coordinate system. Desmos also allows you to use multiple sliders in your constructions. Desmos is a powerful tool for teaching and learning mathematics.
List of features (compare the official website):
Graphing: Plot polar, cartesian, or parametric graphs. There’s no limit to how many expressions you can graph at one time – and you don’t even need to enter expressions in y= form!
Sliders: Adjust values interactively to build intuition, or animate any parameter to visualize its effect on the graph
Tables: Input and plot data, or create an input-output table for any function
Statistics: Find best-fit lines, parabolas, and more.
Zooming: Scale the axes independently or at the same time with the pinch of two fingers, or edit the window size manually to get the perfect window.
Points of Interest: Touch a curve to show maximums, minimums, and points of intersection. Tap the gray points of interest to see their coordinates. Hold and drag along a curve to see the coordinates change under your finger.
Scientific Calculator: Just type in any equation you want to solve and Desmos will show you the answer. It can handle square roots, logs, absolute value, and more.
Inequalities: Plot cartesian and polar inequalities.
Offline: No internet access required.