Updated: Refresher course in lower secondary mathematics! In newly formed 5th grade classes, it often becomes necessary to align different mathematical levels. The transition to upper secondary is a voluntary review of the essential mathematical content from lower secondary education. This course supports students in their start to upper secondary and helps them quickly catch up on any deficits from lower secondary. In a compact format, each topic is covered on ten double pages, including a summary of the fundamental facts, worked-out sample problems, and a series of exercises for practice and review. Solutions for self-checking are included in the appendix!.