SMOPS 2015 No.12 Digits for the Number 2^29
Question
(SMOPS 2015 No.12)
Given that 2^29 is a number comprising of 9 different digits, which digit is not in this number?
Solution (Please refer to Image below)

Please find some interesting selected PMONK Math Olympiad 2013 and 2015 Questions and their ‘poorly handwritten’ solutions (sorry)…
Here is the question & solution attempt:
This sample question is from a well reputed Local Chinese Math Olympiad contest (please pardon my sloppy drawing…
Several people have queried me on this…
(Here’s a detailed possible solution with full explanations for IMO 2016’s Problem 4): *IMO = International Mathematical Olympiad