Take the figure “1” and place behind it a number of “naughts,” thus: 1,000,000,000,000,—as many “naughts” or ciphers as you wish. Then divide the number by the figure “7.” You will find that the result is always this “142,857” then another “142,857,” and so on to infinity, if you wish to carry the calculation that far. These six figures will be repeated over and over again. Then multiply this “142,857” by the figure “7,” and your product will be all nines. Then take any number, and set it down, placing beneath it a reversal of itself and subtract the latter from the former, thus:
117,761,909 90,916,771 ——————————— 26,845,138
and you will find that the result will always reduce to nine, and is always a multiple of 9. Take any number composed of two or more figures, and subtract from it the added sum of its separate figures, and the result is always a multiple of 9, thus:
