PowerPoint enables you to nominate slides as 'hidden'. When you have a slide you do not want it to display when presenting, tagging it as a hidden slide tells presenter mode to skip this slide. But standard PowerPoint does not let you skip the hidden slides in the slide numbers.

PPT Productivity's Manage Slide Numbers and Slide Totals feature for PowerPoint lets you to skip slide numbers on hidden slides. This means that when in PowerPoint presenter mode, your slide numbers will all appear without any indication of slides being hidden.

The Manage Slide Numbers and Slide Totals feature displays the option - you can choose to either skip slide numbers on hidden slides or keep the numbers on all slides.