Find sum of digits of:(1999)^1999.
[The final answer should be a single digit number, for example, (2)^16 = 65536 and the sum of its digits will be given by (6 + 5 + 5 + 3 + 6 = 25, which again will be reduced to 2 + 5 = 7].
(In reply to re(2): super easy
Uh, yes... thanks for the link... my point was that Ady didn't justify the argument... just made a jump to a conclusion. (I wasn't arguing the conclusion ;-).
When one submits a solution.... BEST, he should explain the reasoning behind it... or at least provide a link to justify the conclusion.