Data entry in Excel is quite straightforward. Excel interprets each cell entry as one of the following:
A numeric value (including date and time values)
Text
A Boolean value ( True or False )
A formula
Formulas always begin with an equal sign (=). Excel accommodates habitual 1-2-3 users, however, and accepts an each-at symbol (@), a plus sign (+), or a minus sign ( ˆ’ ) as the first character in a formula. Excel automatically adjusts the entry after you press Enter.