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Neper Multiplication Applet

Genaille-Lucas Applets
(multiplication and division)

 Napier's bones is an abacus created by John Napier for calculation of products and quotients of numbers that was based on Arab mathematics and lattice multiplication used by Matrakci Nasuh in the Umdet-ul Hisab and Fibonacci writing in the Liber Abaci. Also called Rabdology (from Greek ῥάβδoς [r(h)abdos], "rod" and -λογία [logia], "study"). Napier published his version of rods in a work printed in Edinburgh, Scotland, at the end of 1617 entitled Rabdologiæ. Using the multiplication tables embedded in the rods, multiplication can be reduced to addition operations and division to subtractions. (Wikipedia) To obtain the product, simply note, for each place from right to left, the numbers found by adding the digits within the diagonal sections of the strip (using carry-over where the sum is 10 or greater). Example: 46785399 x 7 (Wikipedia) To multiply a multi-digit number by a multi-digit number, calculate partial products and add: Example: 874 x 73 = 874 x 70 + 874 x 3  874 x 7 = 6118 874 x 3 = 2622 add  874 x 70  =    61180 and 874 x 3 =       +2622                      _________ result:                  63802

 Links Napier's bones (Wikipedia) Early Calculation (Ed Thelen) Napier's Bones, Genaille-Lucas Rulers (Georgi Dalakov) Napier's Bones and the Genaille-Lucas Rulers (Brian Borchers) Digitale Rechengeräte Rods for Multiplication and Division Napier Bones in Various Bases (Cut the Knot) Von der Pythagoreischen Rechentafel zu den Neperschen Rechenstäben (Univ. Würzburg) Updated: 2018 Aug 09