Since 2003, the AoPS online school has provided a unique learning experience carefully designed for outstanding students studying online. We offer a full math curriculum for middle and high school, introductory programming courses, and specialty courses to prepare students for particular math and science competitions.
Most age-related problems mention one or more people and one or more points in time (now, in the past, in the future). Write an expression for each possible combination of persons and points in time. For example, if the problem mentions persons A and B and their ages now and 3 years ago then you will write 4 expressions: A's age now; B's age now.