There might be scenarios were you have to show the same presentation to different audience. And you may have slides which are specific to each groups. Instead of removing these slides from the presentation you can hide them so that during the slide show only the relevant slides will be displayed to the individual groups.
Click the Slide Show menu and navigate to Set up section.
Now select the slide or slides that you want to hide and click the Hide Slide menu option. The hidden slides will have a cross mark as shown below.
If you want to unhide any slides, then select the slides and click again on the Hide Slide menu option.