(1) Take a 3 digit number whose first digit is greater than its last.
(2) Reverse the digits of (1) to create a smaller number.
(3) Subtract the number in (2) from (1) (Add a leading zero if this number is not 3 digits)
(4) Reverse the digits of (3)
(5) Add the numbers from steps (3) and (4)
What is the result, and why?
(In reply to re(2): Solution - the Fallacy
brianjn does a good job at demonstrating the composition and decomposition of the number for the five steps. It is usually assumed that numbers are decimal (base-10), yet it is not necessarily the case (especially in a "trick" puzzle). In base-10 the resulting sum for (5) is always 1089. Yet to be more general, in base-r where r is an integer greater than 1, the resulting sum for (5) is r3 + r2 - r - 1.
Posted by Dej Mar
on 2013-04-15 15:59:23