765 chairs are to be arranged in columns in such a way
that the number of chairs in each column should be
equal to the number of columns. How many chairs will
be excluded to make the arrangement possible.
Pure mathematics is the world's best game. It is more absorbing than chess, more of a gamble than poker, and lasts longer than Monopoly. It's free. It can be played anywhere - Archimedes did it in a bathtub.