I could not believe my eyes: Both the question math.stackexchange.com/q/4259077/42969 and the accepted answer are copied verbatim from an earlier thread math.stackexchange.com/q/4258950/42969 (for disclosure: I answered the earlier question). – The author of the copied question even votes to close the original as a duplicate of the copy!
@MartinR I am entirely certain that the system will revert those votes in the next 24 hours---please let me know if it does not (or, you know, don't... I can't see you being incredibly upset by a little extra XP).
@ArcticChar Flag for D8 pending. How could this one be so heavily upvoted ?
Should a question like this , where the complete story is told in a single comment , be multiply answered ? If not, what shall we do. Flag the answers ?
@Peter AFAIK, there is a fairly loose policy on answering in comments. I don't think it is right to judge a question or its answers solely by whether a comment answers the question or not. It is true that the linked question is fairly elementary, but I don't see a problem with that either. But, it is probably a duplicate. (I don't have the time to search for an appropriate duplicate, though.)
@TheAmplitwist Finally, this case is not very serious. One of the two remaining answers has a completely different approach and the other explains how the comments can be applied. Funny in this case is that the author asks for a proof he/she already presented !
@ArcticChar D11 is strange. Does the author claim that the chinese people thousand years ago applied matrix multiplication more suitable than we do today ? Or have I misunderstood something ?
@Peter Oh, so there are deleted answers to the question? I cannot see them, so I did not know. I can't see that OP has proved their observation about the cycling of the units digits in the powers of 2, so I'm guessing they did benefit from the given answers/comments.
@user21820 D9 should go, although quite old. Neither the comments nor the answers are very useful and have hardly to do something with the question.
@TheAmplitwist One of the deleted answers summarizes the authors observation and mentiones the possibility with the $5$ and one suggest induction but then admits that contradiction using prime factor $5$ is better. Not very useful since this was already pointed out (apart from the induction approach)
@Peter Gone; the one following it needs one more delete vote; and I can't even vote on the third listed, since I already voted to close last time around :(
@Peter one of the answers there is up for deletion.
