You must use placeholders when you create the slides. The formatting on the
master slide affects the placeholders on the slides. Placeholders are those
boxes that say "click to add text."

If you just created a textbox using the textbox tool on the Drawing toolbar,
then that text won't react to changes you make on the master slide.

You can try re-applying the bulleted slide layout and see if that makes the
slides take on the master formatting. If you used the placeholders when you
created the slides, it should. Actually, apply the slide layout twice, as
that's sometimes necessary to overcome manual formatting.

GO to Your Master Slide obliterate only the page number
Inside the Master Slide Right click
Master Layout
Make a mark on the Slide number