When you need to do a quick calculation normally you would think to use the Windows calculator. Start by placing your insertion point into the blank top cell in the Total column. To add the formula in the Word table do the following.
It would be nice if after entering the numbers in each column Word would automatically show the total.
Then continue to click the drop-down button and choose a number format for the value. We will be inserting the sum of a column of values into the cell below those values behind the word Total Including the word Total is optional but can be helpful in identifying information in the table. Unfortunately this formula would simply add all the numbers to. This will display a Formula Dialog Box which will suggest a default formula which is SUM LEFT in our case.