Learn It Yourself First. As a mature and motivated adult, you may find it quite possible and enjoyable to learn algebra, geometry, etc., in a fraction of the time it takes in high school. You and your student can help each other learn as a team. Your student can study independently, using texts that present concepts clearly. Answer keys that show all the steps to complete each problem are helpful.
Correspondence courses add accountability and feedback to independent study.
For immediate help when needed, your student can call on you, a friend, a tutor, or even another student who can explain whatever he is stuck on. Learn by Teaching. Have your student teach you what he is learning. Textbooks and Workbooks. In addition to a good, solid textbook, consider using one or more workbooks or texts from another source for reference.