The tables in the spreadsheets usually contain formulas that are used in tha background to find totals, averages etc. Graphs of various types including pi charts, histograms etc can be used to ilustrate the data in any given table. Hence a completed spreadsheet acts like a template in which the old data can be replaced by new and a new situation may be analysed very quickly.
The most commonly-used spreadsheet software packages are Microsoft Excel and Corel Quattro-Pro. For further information, books on these topics are listed on science-books.net.