There was a time when, to sum a column or row of numbers in a table, you probably did it manually or used a VBA macro. These days, Word has a nifty little function called Formula in the Layout tab.
To use the function, you need to position your cursor in the cell in which the total is to be placed and select Formula.
Here is the function with a description:
For our purposes we need SUM(LEFT):
Select the number format and hit OK. The total is now showing in the last column.
To get totals for the cells below, you will need to repeat the process. However, the formula offered will assume SUM(ABOVE), because it thinks you’re totalling a column, so you need to change it to SUM(LEFT).
When you’re finished, you can if needed sum all the columns, like this:
If any of the values are changed, the totals adjust automatically.