Users interact with sheets primarily through the cells. A given cell can hold data by simply entering it in, or a formula, which is normally created by preceding the text with an equals sign. Data might include the string of text codice_1, the number codice_2 or the date codice_3. A formula would begin with the equals sign, codice_4, but this would normally be invisible because the display shows the "result" of the calculation, codice_5 in this case, not the formula itself. This may lead to confusion in some cases.