This is necessary because you want to allow for the occasions when a column heading might also be a cell reference. For example, if you were entering in data about different British roads you may want a column heading saying 'A1'. The spreadsheet has a number of advantages over other methods of performing numerical calculations. Let's take the simple example of a shopping list, as shown in Figure 2. Figure 2 A Spreadsheet Used With A Shopping List.
Some advantages are immediately obvious.
Firstly, all the numbers are visible and can be checked for errors and corrected - unlike a calculator where the number disappears as soon as you perform the calculation. Secondly you can label the numbers with some text to identify what the numbers relate to. The calculation is set up the with the result appearing at the bottom of the column. This in itself is not much of an advance on any other calculating mechanism. This is illustrated in Figure 3.