If we assume algebra is a way of using variables and operations to represent quantities in equations, then at least one of the apps I downloaded is actually one that has students solving problems using mental math within a specific time period. In a sense this goes against what we try to teach our students which is show all your steps.
So today I'm looking at Algebra Study Cards, an app that allows you to select which operation you want to practice. They use the variable X in all equations. Most of the problems I've seen are all one step or combining constants and then finding the value of X
As you progress through this, the problems get harder and more complex. Notice the one to the left which has you figure out the 5 - 10 before you can solve for x within a 10 second time limit.
If a student needs more time to mentally solve the problem, they might get frustrated with the 10 second and give up. I still need to figure out if you can change the time limit on the game.
It does require combining like terms before you can solve. It also has both positive and negative numbers for what the problem equals. Most of my students are scared of negative numbers and need the practice.
Due to when I learned algebra, I still have problems with the idea that a person should practice solving for the value of x without any written work, especially since many of the new tests require students to explain or justify their answers. As mentioned earlier, the time limit might frustrate students who need more time and if their answer is wrong, they won't know why because the program flashes the correct answer.
The bottom line, is that I'm not sure its one I'd use in class. I have to think about it.