You can′t divide 21 by 12

or, How base can you get?

Can we find a base in which 21 can be divided by 12 without remainder? And why should we? - Because someone said it couldn't be done. They may well have meant that it can't be done if the base is a positive number - and in fact, if you use base (-5) then 21 = 3 x 12 is true.

Which led me to look at some other results in other bases - not recent discoveries, I might add; the keyboard is ready and willing to work, but occasional bursts of lethargy often hit the typist, in particular Nap Attacks as favoured by Garfield.(1)