Functions in Microsoft Excel

Function:

In mathematics, a function is a relation or expression involving one or more variables. It is the idealization of how a varying quantity depends on another quantity.

Excel can perform a large number of these functions.

They can be inserted by clicking on the "Insert Function" icon.

Functions menu will appear from which you select the desired function for use.

You can select the category from the drop-down menu and then the function from the bottom window.
Like for sum function, select Math & Trig from the category or select Most recently used if you have already used the sum function recently; Then select the sum from function box and click OK.

A new dialouge box will appear where you can add the number you want to apply function on. You can select as much numbers as the function allows. After selection of data click on OK and your function will be applied to you data.