SUM Function

For this function, go to where you wanted the result should be displayed.

Then, at Formula tab, go to Function Library group and click AutoSum.

Upon click, the formula will be displayed as follow.

Press Enter to accept.

Other than using function button from the menu, you can type in the formula as follow.

To select the SUM function, press TAB on your keyboard and you should see something like this.

Then, click and drag with your mouse from E2 to E6.

SUM function is the only function that had its own shortcut. To use it, select where you wanted the function to be placed. At your keyboard, press ALT and + at the same time.

You could see something like this:

It will automatically select data to be summed up. You may edit it by click and drag if you found out that the cells / range selected is out of your focus.