Napier’s bones
Napier’s bones were a calculating device much used in the 16th century, just after place notation with arabic numerals had replaced Roman numerals. You could replace a long multiplication problem with a series of additions and multiplications by 10, 100 and so on. The Wikipedia article for Napier’s Bones has details, references and diagrams.
- Alexander Bogolmony’s Cut the Knot Web site has a large number of illustrations of Maths using Java applets
- The Napier’s Bones page has a Java applet where you can change the bones.
- Undusting Napier’s Bones Greg Michaelson has provided a more extensive biography of Napier – alas his Java simulation does not appear to be working at least with the Java machine on this browser.
The implication is that 16th century businessmen found remembering their tables hard work and welcomed a short cut. Food for thought for those devising the “functional core” of Maths that will soon form part of the newly rewritten GCSE?