Here is how to use "Watch Window" in Excel (2013 version):
Adding a Watch Window
Select the cells you want to watch
On the Formula tab, in the Formula Auditing group, click on Watch Window
Click Add Watch ant then click Add
Note: You can move the Watch Window toolbar to the top, bottom, right or left side.
To display the cell that an entry in Watch Window toolbar refer to, double click the entry.
Removing cells from the Watch Window
Select cell that you like to remove. To select multiple cell, press CTRL and then click the cells
Click Delete Watch