Test your algebra skills, and train the four basic mathematical operations.
You can also choose if you want to separately train the addition, the division, the multiplication or the division.
This app is useful for both kids learning the basic operations and adults willing to do some mental gymnastics.
There is also a nice feature that will help you learn from your mistakes: if you click the wrong answer, you can be sure that the wrongly answered question will be asked you again soon, so you have the possibility to answer correctly the next time (and learn!).
Added more complex questions with 3 and 4 operators.