Solution

(related to Problem: Simple Multiplication)

The number required is $3,529,411,764,705,882,$ which may be multiplied by $3$ and divided by $2,$ by the simple expedient of removing the $3$ from one end of the row to the other. If you want a longer number, you can increase this one to any extent by repeating the sixteen figures in the same order.


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References

Project Gutenberg

  1. Dudeney, H. E.: "Amusements in Mathematics", The Authors' Club, 1917

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