To do Alt + M U on Mac in Excel, download and install Accelerator Keys, then press Option, followed by M, U.
Command: AutoSum Menu
This is how to do Alt + M U on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + M U opens the AutoSum dropdown menu in Excel’s Formulas tab. This menu provides quick access to common aggregation functions including Sum, Average, Count Numbers, Max, and Min. It’s a fast way to insert frequently used formulas without having to type them manually.