Think before you add slide numbers
The answer was: Nothing. The slide numbers did not help explain the ideas or help the audience understand the message. The only time I think slide numbers are useful is when you are presenting using a flipbook (where the slides are printed one per page and the presentation is done flipping through the book of slides). In this case, it can be helpful to keep everyone on track by referring to what slide number you are on.
But if you are presenting in a room with a projector, slide numbers are not necessary. If the audience has a handout, they have a copy of your slides or notes and you will refer them to a page number in the handout, not the slide number. If you don’t have a handout, the slide numbers serve no purpose to the audience.
What do you think? If you use slide numbers, what benefit do they have for your audience? Add your thoughts in the comments below.