When I started programming (with Python) I remember how the modulo operator was introduced, without any further information. I found it quite confusing, since I didn't know what modulo meant (that could be solved with googling) but more important, how it was useful. When you come from a CS perspective, it's completly clear on how you can use it and why it is essential for some computing tasks, but for a non-CS beginner that can be much more obscure.