### Theory:

function is a predefined calculation entered in a cell to help you analyse or manipulate data. All you have to do is enter the values, and the calculation is automatically made for you. Functions help you create the formulae required to get the results that you are looking for.

Functions can be used to perform simple or complex calculations. You can use different formulae in LibreOffice Calc. A formula in LibreOffice Calc starts with an equal to ($$=$$) sign.

Statistical Functions:

LibreOffice Calc includes over $$70$$ statistical functions which enable the evaluation of data from simple arithmetic calculations, such as averaging, to advanced distribution and probability computations.

Some of them are:

SUM Function:

It calculates the total of a given set of values.

The SUM function is very basic and easy to understand. You may add it manually to a field instead to speed things up.

Steps to insert SUM Function:
• Select the Insert option from the menu bar and select the Function List. LibreOffice Calc displays functions in a sidebar that it attaches to the right of the spreadsheet. • Select the option "Mathematical" from the category list and select SUM from the Function list. • Click the Next button.
• Click the mouse button and select the fields that you want to calculate the sum.  • Click Ok to finish the insert SUM function. You may add it manually to a field instead to speed things up.

Syntax:

$$=SUM(XY:XZ)$$

Example:

To calculate the sum of the five fields$$A1 to A5$$, you use the function:

$$=SUM(A1:A5)$$ 