Feynman Long Division Puzzles
Encyclopedia
Physicist Richard Feynman
Richard Feynman
Richard Phillips Feynman was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics...

 sent the following puzzle for his father attached to a letter to his mother in 1939

.

Each digit of a long division
Long division
In arithmetic, long division is a standard procedure suitable for dividing simple or complex multidigit numbers. It breaks down a division problem into a series of easier steps. As in all division problems, one number, called the dividend, is divided by another, called the divisor, producing a...

 has been replaced by a dot or the letter A (which stands for a unique digit). None of the dots are the same as the A digit. The goal is to reconstruct the original figures. The algorithm commonly used in the US calls for the quotient
Quotient
In mathematics, a quotient is the result of division. For example, when dividing 6 by 3, the quotient is 2, while 6 is called the dividend, and 3 the divisor. The quotient further is expressed as the number of times the divisor divides into the dividend e.g. The quotient of 6 and 2 is also 3.A...

 to be in the first line, the divisor to be in front of the ) and the dividend behind it. The quotient is thus (....A..):(.A.) = (..A.)

Here is the division:


However, Feynman was not the author of this particular puzzle since the same skeleton division had been previously proposed as problem E217 in the May 1936 issue of the American Mathematical Monthly
American Mathematical Monthly
The American Mathematical Monthly is a mathematical journal founded by Benjamin Finkel in 1894. It is currently published 10 times each year by the Mathematical Association of America....

by W. F. Cheney, Jr. and its solution by M. J. Turner was later published in the February 1937 issue of the same journal, long before Richard Feynman's letter.

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