Apple - How to add shortcut for Insert Equation in PowerPoint 2016?

The shortcut posted by theoden seems to be broken in new versions. As a workaround one can just go to the System Preferences => Keyboard => Shortcuts => App Shortcuts and add another one for Microsoft PowerPoint with the "Equation" as Menu Title.

This shortcut is already in PowerPoint: ⌘Option=

This produces a place to type an equation when you are in a text box.

You can't post keyboard shortcuts into comments, so I added an answer. I found out about the German keyboard shortcut (by trial and error). It is: ⌘alt´

So, on a German keyboard the equals sign has to be replaced with an apostrophe (the key next to the backspace key (on its left)) @Daniel