Calligra Sheets has a huge range of built in mathematical and other functions that can be used in a formula cell. They can be seen and accessed by selecting a cell then choosing Function... from the Insert menu. This brings up the Function dialog box.

Select the function you want to use from the listbox at the left of the dialog box. The Help tab page will then display a description, the return type, Syntax, Parameters, and Examples for this function. In addition this page provides often links to Related Functions. Then press the button with the down arrow key symbol on it to paste it into the text edit box at the bottom of the dialog.

The Parameters tab page will then be displayed to let you enter the parameter(s) for the function you have just chosen. If you want to enter an actual value for a parameter, just type it into the appropriate text box in the Parameters page. To enter a cell reference rather than a value, left click on the appropriate text box in the Parameters page; then left click on the target cell in the spreadsheet.

Instead of using the Parameters page, cell references such as B6 can be entered by typing them directly into the edit box at the bottom of the Function dialog. If a function has more than one parameter separate them with a semi-colon (;).

Pressing the OK button will insert the function into the current cell and close the Function dialog.

You can of course do without the Function dialog and simply type the complete expression into the main text entry box in the Cell Editor tool options. Function names are not case sensitive. Do not forget that all expressions must start with an = symbol.

Logical functions such as IF(), AND(), OR() take parameters which have the logical (boolean) values True or False. This type of value can be produced by other logical functions such as ISEVEN() or by the comparison of values in spreadsheet cells using the comparison expressions given in the following table.

Thus if you enter =IF(B3>B1;"BIGGER";"") into a cell it will display BIGGER if the value in B3 is greater than that in B1, otherwise the cell will show nothing.

If a formula contains a cell reference that reference will normally be changed when the cell is copied to another part of the worksheet. To prevent this behavior put a $ symbol before the column letter, row number or both.

When you are entering or editing a cell reference in a formula the shortcut key F4 can be used to step through these four possibilities.

Named cells can be used in a similar way to include a unchanging cell reference in a formula.