In this section will be examined some calculating tools, used by mankind in the past 2000 years. Of course we will start with the abacus, the most famous and of longest use calculating tool. Then will be examined two of the inventions of the Scottish nobleman John Napier—Napier's bones (Napier's rods) and the logarithms. In the section Gadgets will be examined all sorts of calculating tools, as well as quite a few simpler and not so important calculating machines, which didn't found their place in the section of mechanical calculators. Some place is also dedicated to the analog computers.

Seek simplicity, and distrust it.
Alfred North Whitehead (1861–1947)