Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 165
and subtract (or add) the complementary number from(or to) the place in question. In first experimenting with the Soroban, anoperator who is accustomed only to our Western modes of figuring is apt toadd mentally, and then set down the result on the instrument. Such a modeis inferior of course to… … Fig. 5. But if anyone will take the trouble to dispossess himself of his Westernmethods and work in the manner indicated, he will find Soroban addition andsubtraction both more rapid and more certain, because attended by lessmental exertion, than in figuring. The one seeming disadvantage in…
