Brazilian mathematician Inder Taneja has found a way of expressing every number between 1 and 11,111, except 10,958, by inserting mathematical operators in between the numbers 1 2 3 4 5 6 7 8 9 and evaluating the expression. He did so using the four basic arithmetic operations, exponentiation, concatenation, and brackets, but avoiding factorials, square roots, and decimals. If these last three operations are allowed, can 10,958 be likewise expressed?
Matt Parker from the Numberphile YouTube channel found a solution and explains it in this video.
|| stands for concatenation. (ie:
1||0 x 2 = 20)
1 x 23 + ((4x5x6)||7 + 8) x 9
Concatenation is heavily used in the paper but I don't think it ever have been used that way. (ie:
(2 x 3) || 2 = 62)
Does it's stand with the spirit of the paper? It's debatable.