Online Math Tools

Geometric Construction
sciencevsmagic starts you with two points. You can draw a line segment between them, or make a circle with one as center, going through the other (start at the center point and head just above or below the point you want on the circle). Intersections of circles add new points. There are 40 challenges in sets of 4.

euclidea has even more challenges. They must be done in order. Quit when you get stuck and come back later.

geogebra is the most open-ended. If you're hooked on drawing geometric figures, this can do anything.


Graphing
desmos.com (marbleslides, make your icon)


Simple Programming
Make a square, hexagon, and circle in scratch.