You can add totals to a table by selecting the Total Row checkbox on the Design tab. You can also add a function from the total row drop-down.
Select a cell in a table.
Select Design > Total Row.
The Total row is added to the bottom of the table.
Note: To add a new row, uncheck the Total Row checkbox, add the row, and then recheck the Total Row checkbox.
From the total row drop-down, you can select a function, like Average, Count, Count Numbers, Max, Min, Sum, StdDev, Var, and more.