Sometimes it comes in handy to use numbers within your text to refer to numbers in your diagram. Like this slide.
You might just use a circle shape with a number inside it. But then, when you update the text, you also have to move the circle around manually. Time-consuming!
Instead, use the Windings2 font. It creates a number inside a circle that stays in place even as you update your text. You can also change the font size without having to resize the circle. Here’s a handy printable cheat sheet.