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 Format → Sheet → Sheet Properties 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 Function... from the Insert 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 =SUM(B4:C10) calculates the sum of all values in the cell area B4 to 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.