In the context of spreadsheets data is anything that can be entered into a cell. The catagories of data used when working with spreadsheets are numbers, text, formulas, dates, and times.
Numbers – constant values you enter into a cell. The following are numeric entries: 3, -5, 3E6, 5.25.
Text – any string of characters that contains at least one nonnumeric character. If you precede an entry with a single-quote mark (') the entry will be interpreted as text and the quote mark will only show up while you are editing the cell. The following are text entries: Total, 337 66, 5-10, 10AD, '711, SUM(a1:a5).
Formulas – equations that compute a value from cell references, names, functions, and operators. A formula produces a new value from existing values. In Excel a formula is always preceded by an equal sign (=). The following are formulas: =A1, =1+2, =AVERAGE(88,99), =SUM(a1:a5), =A5-PrevTotal. (In the last example "PrevTotal" is a reference to a named cell.)
Dates and Times – Dates and times are stored as numbers. It is the format of the cell (more specifically, the number format) that determines how the value is displayed. For example, if you entered a valid Date format such as 11/28/96, the Number format of the cell would change to Date and 11/28/96 would be displayed. If you changed the Number format to General, 35397 would be displayed. Where did this number come from? As we said earlier, date and time values are stored as numbers. 35397 is the number of days since 0/0/00. So, date and time values are not really a new data type, but instead are numeric data displayed with a different format.