Students have the choice of solving the problem two ways. They can solve it using the tradition way.
Or with the variable covered up so you can solve the problem by seeing what is missing.
This next shot is from level 5.
So this app would work for students from pre-algebra to algebra 2 or even higher. It will work for practice, remediation or reinforcement.
They are still preparing my iPads and the tech dept requested a list of apps so I went looking and found several new apps that look really nice by the center for algebraic thought and these apps are free.