no slide numbers

One important small thing that was often missed in the presentations I saw in the last time was the numbering of slides.

During a presentation people try to listen to the talk of the presenter (given she is engaging enough). But because we usually - at least in university - have to give monologues, disruptions are uncommon and questions are done at the end of a talk.

Lets imagine that I did not understand some minor detail at a slide in the first half of the talk. If there are no slide numbers I now will have to discribe somehow the design/ content of the respective slide to give the presenter an idea about what I am talking about. So I do not only need to keep my actual question in mind (or on a paper) but also have to make remember (or sketch) the corresponding slide.

In contrast if there are numbers, I just have to scribble the digits besides my notes and when it is finally time for questions we do not figure out where the slide was. Instead the author can directly jump to the slide (in Powerpoint this is done with <number>+ENTER) and we both can concentrate on discussing the topic of the given question.