Coding Sites.
https://www.tynker.com/
www.code.org . and https://hourofcode.com/us/learn
https://www.playcodemonkey.com/hour-of-code/coding-adventure/
https://www.mathplayground.com/ . Another math site.
Art Sites.
https://sketch.io/sketchpad/ . For older students.
https://www.autodraw.com/