Quick Method to Add Numbers in Word 

Word has a hidden feature that can add selected numbers in a list and display the sum on the status bar. Even better, if you press Ctrl + V, the sum, which was added to the Clipboard, pastes into the document.  

From the Tools menu, choose Customize. Select the Commands tab.  Under Categories, select Tools and locate ToolsCalculate under the Commands list.  Click and drag the ToolsCalculate button onto an existing toolbar and release the mouse.  Close the Customize dialog box.  (You can modify the text button to one of the built-in icon buttons while still in the Customize dialog box.)

Note:  You can click and drag icons to the Menu Bar, not just Toolbars. 

On an empty line in the document, type 41 and press Enter. Type 89 and press Enter. Type 119 and press Enter.  Select the list of numbers, then click the Tools Calculate button and view the resulting sum on the status bar.  Press Ctrl + V to paste the calculated result in the document.