By default, Keynote slides are numbered in a white text. I can change the slide number text color by selecting the text, format, and change text color. Apparently, I have to do this one slide at a time. Is there an easy way to change all of the slide number colors with one formatting operation instead of one slide at a time?
I want to more efficiently change all slide number color instead of the time consuming requirement of one at a time.
Yes. Change the first one. Then select the text in it. Look at the right sidebar and make sure you are viewing the Format sidebar, then under that the Text portion. You'll see that the text you have selected is of the style "Slide Number." Next to that style, since you have changed it for this case, there will be an "Update" button. Click that and the Slide Number style will change, thus changing the style of all of the rest as well.
See https://macmost.com/how-to-use-styles-in-pages.html for a tutorial on Styles. Pages is used in that tutorial, but learning how Styles work will serve you well in Keynote too.
Thanks Gary, so simple and I learned something!