Family of Problems is dedicated to building a warehouse of creative, interactive, flexible problems for innovative math teachers. All the problems within this site have been successfully used by experienced math teachers in the classroom. Problems are grouped in threes based upon related content and learning concepts. Each problem is documented with a front door, lesson plan, and black line master; and links to its two closely related problems. The problems are listed below organized by grade level, big idea, and alphabetic order. Enjoy!