Practice adding and subtracting positive and negative integers.
This project was inspired by and is based on the Add relative integer project by hilaire.
Pretty good. Two things tripped me up ... I thought clicking plus and minus would actually move by one. Perhaps make the "sign" more obvious?
The other was my own ignorance. I thought the parentheses meant "do me first" as they do in programming :) Forgot they meant minus in school.
Getting rid of the middle state is improvement, I think.
If the controls are "face toward positive", "face toward negative", "move forward" and "move backward", (and possibly "repeat n times"), you can use this idea to teach not only addition and subtraction but multiplication and why a negative number multiplied by another negative number is a positive number.
Website contents under a Creative Commons license.