Depending on your computer's Operating System there are different ways to know which browser version you are using.
A. From a Mac (OS X):
1. With the browser open, select the Title of the browser in the top left hand corner of your screen, next to the () Apple icon
2. Select About Application (application being the name of your browser)
3. From here you should see technical details about the browser, note down the Version number (Ex. Version 14.01.028)
B. From a PC (Windows):
1. With the browser open and from the menu bar, click Help and then select About Application
2. The browser version will be displayed in the information screen, note down the Version number