The phrase refers to a digital document, specifically a PDF, containing solutions to the exercises found within a particular level of the Kumon curriculum. Level D typically corresponds to material covering multiplication, division, fractions, and basic algebra concepts. These solution manuals serve as resources for parents or instructors to check student work and identify areas where additional support might be necessary.
Access to solution keys provides several benefits. It allows for efficient grading, reduces the time spent manually verifying answers, and enables a more detailed analysis of a student’s understanding of the core mathematical principles. Furthermore, it can facilitate independent learning by empowering students to review their work and correct errors with guidance.