126.--SIMPLE MULTIPLICATION.

From Amusements in Mathematics by Henry Ernest Dudeney.

If we number six cards 1, 2, 4, 5, 7, and 8, and arrange them on the table in this order:--

1 4 2 8 5 7

We can demonstrate that in order to multiply by 3 all that is necessary is to remove the 1 to the other end of the row, and the thing is done. The answer is 428571. Can you find a number that, when multiplied by 3 and divided by 2, the answer will be the same as if we removed the first card (which in this case is to be a 3) From the beginning of the row to the end?

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126.--SIMPLE MULTIPLICATION.: Amusements in Mathematics by Henry Ernest Dudeney | amphi