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Genaille-Lucas Multiplication Applet

Division Applet





Genaille–Lucas rulers (also known as Genaille's rods) is an arithmetic tool invented by Henri Genaille, a French railway engineer, in 1891. The device is a variant of Napier's bones.

Genaille Lucas Rulers
                  Multiplication

By representing the carry graphically, the user can read off the results of simple multiplication problems directly, with no intermediate mental calculations.

Example: 874 x 7

Start reading the result by the
first number in the right hand column (8),
and follow the triangles:

top
             multiply



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

multiply

  multiplication
874 x 7 = 6118
874 x 3 = 2622

add    :             61180

                       +2622
                     _________

result:             63802



Genaille Lucas rods


Links


Genaille–Lucas rulers (Wikipedia)

Early Calculation (Ed Thelen)

Napier's Bones, Genaille-Lucas Rulers (Georgi Dalakov)

Napier's Bones and the Genaille-Lucas Rulers (Brian Borchers)

Qui est Henri Genaille?

Digitale Rechengeräte

Rods for Multiplication and Division


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Updated: 2013 May 13