If you have a slide that you want to keep in your PowerPoint deck but don’t want to show them in a presentation, you can hide those slides.
Go to the strip of slide thumbnails down the side of your project and select the slide you want to hide. You can select multiple slides using Control+Click or Shift+Click.
Right-click and select Hide Slide.
Alternatively, you can go to the Slide Show tab and select Hide Slide.
Which Slides are Hidden?
To see at a glance which slides in your presentation are hidden, look at the numbers next to them on the left. For any hidden slides, the number will have a diagonal line through it.
To show a hidden slide again, select it and go to Slide Show | Hide Slide again to unhide it.
The Hide Slide item on the right-click menu is an on/off toggle though the difference isn’t visually obvious.
If you want to unhide all your hidden slides in one go, click any slide and type Control+A to select all slides.
Then go to Slide Show and click Hide Slide twice (the first click will hide all the slides, and the second click will unhide them all.)