If the first character in a cell is an equals sign (**=**)
Calligra Sheets will take the cell contents to be a formula which is to be
calculated. The result of the calculation will be displayed in the cell rather
than the formula itself. For example, enter ** =2+3**
into a cell and it should display

*5*.

More usefully, a formula can contain references to other cells, so
that ** =B4+A3** will calculate the sum of the values in
cells B4 and A3, and this calculation will be updated whenever cells B4 or A3
are changed.

As well as addition, a formula can make use of the **-**
symbol for subtraction, ***** for multiplication, and **
/** to perform division. The round bracket symbols **(**
and **)** can also be used as in normal algebra, so you could
enter more complex formulae such as ** =((B10 + C3) *5 - F11) / 2
**.

Cells containing a formula will be marked with a small blue triangle at the bottom left corner if the Show formula indicator check box in the → → dialog is checked.

Calligra Sheets also includes a large number of built-in functions for applications such as statistical, trigonometrical and financial calculations. Their use will be examined in more depth in a later section of this manual, but if you are interested at this stage choose from the menu and take a look through the Function dialog box that will be displayed.

For the time being, however, the ** SUM** function may
be of interest as it calculates the sum of all values in a specified area of
cells. For example

**calculates the sum of all values in the cell area B4 to C10.**

`=SUM(B4:C10)`

If Calligra Sheets displays **#VALUE!** when you have
entered your formula this usually means that it cannot understand what
you have entered, but if the row of symbols ends with a
small red arrow this just means that the cell is not wide enough to display
the complete result, in which case you should either make the cell(s) wider
or change their format so that the result
does fit properly.

If the Automatic recalculation box in the → → dialog box is checked, Calligra Sheets will recalculate the values of cells whenever anything that affects them is changed in the sheet.

When Automatic recalculation is not checked for the
current sheet, you can instruct Calligra Sheets to perform a recalculation at any time by
using the or option in the
menu or their shortcuts **Shift**+F9 or F9.