There are 1000 lockers in a junior high school..
the lockers are numbered consecutively from 1 to
1000. there are 1000 students in the school. the
first student opens every locker. the second
student closes every second locker. the third
student'"undoes" every third locker, that is, if the
locker is open, he closes it and if it is closed, he
opens it. all 1000 students line up and perform an
action on a locker-the tenth student "does"
something to every tenth locker. what does the
one-thousandth student do to the one thousandth
locker?