To do Alt + H U on Mac in Excel, download and install Accelerator Keys, then press Option, followed by H and U.
Command: AutoSum Menu
This is how to do Alt + H 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 + H U opens the AutoSum dropdown menu, providing quick access to common aggregate functions. From here you can select Sum, Average, Count Numbers, Max, Min, or More Functions to automatically create formulas for your selected data range.