Now go to the first row last column and choose Table Tools Layout Formula. You can use a Word table and let Word do the calculating. Just switch to Insert tab and click Equation Insert New Equation to toggle on Equation Tools.
You can type in the Formula box select a number format from the Number Format list and paste in functions and bookmarks using the Paste Function and Paste Bookmark lists.
Linking an Excel worksheet is the best way to get Excel data into Word because Excel is the best tool for working with spreadsheets. From the top menu select Insert Object Create New. Click OK to accept the settings and insert the formula into the cell. In the Formula box check the text between the parentheses to make sure Word includes the cells you want to sum and click OK.