I’ve decided to review Algebra Balance Scales found at http://nlvm.usu.edu/en/nav/frames_asid_201_g_3_t_2.html?open=instructions&from=category_g_3_t_2.html
The purpose of this game is to solve simple linear equations by placing virtual manipulatives on a balance beam. When the beam is balanced, the player then solves for x. Students soon realize that any operation done to one side must be done to the other to keep the beam balanced.
I think this applet would be excellent for students who need more practice with solving linear equations. The site also has another version of the Algebra Balance Scales game that has problems with negatives. I find many children and adults who need extra help when working with negative numbers. My district doesn’t have math manipulatives, so this Applet would be an inexpensive way to give those students, who learn best by working with concrete examples, the opportunity to do so.