If you need to make simple presentations on the move, Presentation Maker for Android devices is worth trying.
Presentation Maker claims to be a "mobile version of Powerpoint" and while it's certainly not that, it is useful for very basic slideshows.
All of the basic tools you need are there - Text, Insert Images, Transitions and Markers etc. What you won't find are tools to crop images or add audio or multimedia. For quick and basic slideshows on the move, Presentation Maker does the job.