Proof of Multiplication in Ten Seconds.

30 Oct 2023

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Proof of Multiplication in Ten Seconds.

The unitate of a number is the sum of its digits reduced to a unit.

The unitate of the multiplier is 9 and the unitate of the multiplicand is 6; 6 times 9 equals 54, and the unitate of 54 is 9. Now the unitate of the product is found to be 9 also, which is a proof of the correctness of the work.

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This book is part of the public domain. Anonymous (2021). How to become a lightning calculator. Urbana, Illinois: Project Gutenberg. Retrieved

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