Given that
2^29 is a ninedigit number all of whose digits are distinct,
determine which of the ten digits is
missing.
Provide your answer without computing the actual number.
Source: SMO contest
(In reply to
re(2): Solution by Jer)
lol, yeah, didn't think of the power of 2 thing. When I read proofs/solutions I tend to see the logic/reasoning in my head in a much more general manner and thus some of the obvious assumptions like that get lost to me.

Posted by Daniel
on 20150609 13:33:51 