Infinite Algebra is an interactive software which teaches you math.
Very useful as a teaching aid when used in combination with an LCD projector or other display system. One to four questions at a time are shown on the screen. Print multiple versions of an assignment. You control how each new version is created: scramble the choices, scramble the questions, or make completely new questions. You can also save each new version after it is created. Proportionally increase or decrease the number of questions in the assignment. This is very useful when planning a lesson. You can create a few questions to use as examples, and then scale up the number of question to create a homework assignment. The questions on the homework will be completely new, yet follow precisely from the lesson--and you don't need to design the questions again.