Solve for X. This app is different from most of the apps I've run across in that it requires the student to tell the app the next step.
The app has six levels. The first level has students solving one step equations. You have to complete a certain number of problems correctly before you can unlock the next level.
The second level has students solving 2 step equations using addition or subtraction first, followed by the multiplication or division. It isn't until you get to the third level that fractions are involved. The interesting thing about this app is if you put in the wrong numbers, add 3 instead of subtracting 3, it will do exactly what you said and you can see what the results.
This app will allow my students to practice solving equations and I can use it to help reinforce and differentiate instruction.