This answer:
Adding mAh when wiring battery cells in series?
has a typo: "43" instead of "3":
a 1500 mAh cell will provide 1500 mA for one hour or 500 mA for 43 hours or 850 mA for 2 hours
Trying to correct the typo gives this response while editing:
Oops! Your edit couldn't be submitted because: * Edits must be at least 6 characters; is there something else to improve in this post?
lol, adding whitespace to the end of the post changes the message to:
* Edits must be at least 6 non-space characters; is there something else to improve in this post?
It seems SO should allow edits shorter than 6 numeric characters if that is indeed the proper change. Conveniently in this case there was a "____" separator so adding 5 more underscores solved everything tidily.
Note also that this is not a trivial edit, but one that changes an incorrect answer into a correct answer. In other words, math spelling errors are not trivial.