How to Change the First Slide Number in PowerPoint 2010
If you need to change the first slide number (normally the cover) to start from 0 instead of 1, then here we will try to explain how you can achieve this change.
In PowerPoint 2010 you can apply this change from the Design tab. Under this tab, go to Page Setup and then change the value for Number slides from, from 1 to 0 as shown in the figure below.
If you have a sequence of independent presentation files and want to start each file from a different number then you can also change the value to another positive value. For example, if your first presentation has 50 slides and want to start another presentation from slide 51 then you will enter 51 instead of 1. This helps to keep consistency between different presentation files.
If you are using a previous version of PowerPoint like MS Office PowerPoint 2007 then you can change this value from the Design tab on the toolbar and then go to Page Setup in the same way.