This is a unit-specific exercise book for Teiryo-kai's 2023 high school sophomore (K2) math course. It's a home study material for reviewing the content covered in the first semester of K2 math. Please refer to the first photo for the unit names. There are no markings. However, the original booklet of problems and answer/explanation sheets were stapled together, but they have been separated. Please be aware of this. The answer/explanation sheets are packed with key points from Teiryo-kai's K2 math first semester and provide very clear explanations.