This document constitutes the second and final version of the Smart Learning Atoms (SLA) report of the MaTHiSiS project. The SLA, which is central to the approach taken in the MaTHiSiS project, is an atomic and independent piece of knowledge or skill that will allow the users of the MaTHiSiS system to re-use their work in other similarly structured learning scenarios, as is often the case in modern schools or work environments.