Lcm? in alpha course- never defined

Goes on and on about lcm. I have no idea what LCM is. I am about to find it in the ruby standard library so I know and it also isn’t like this is a barrier for me to understand what the page is teaching, but it is poor form to reference undefined ideas and methods in a teaching course.

If App Academy is hiring I would be thrilled to fix the language used and to organize the curriculum into a logical way(Walking through it for a first time I am well acquainted with pacing issues etc)