hihi, all - in 1974 or so, i taught a calculus for non-physical science majors at U. Wisconsin Madison after a couple of months of doing derivatives and integrals, i was talking about some problem or other, and said ``the limit of this expression is ...'' one of the students piped up and asked ``how do you know?'' i gave them an intentionally incomplete answer about getting close, and another student pushed me on that, and over the course of an entire hour, (well maybe half an hour), the class collectively pinned me to the wall until i wrote out the entire epsilon delta definition of limits, and they said ``why is that so hard?'' - it was one of the most remarkable class sessions i have ever been in getting close how close always close or just sometimes eventually always close than this as a second suggestion, i also taught an honors calculus class there for two semesters - in my class, every homework and every quiz and every test had a mathematical induction problem, initially as extra credit in the second semester, i got the runoff from two parallel first semester classes, one of them mine - so i put an induction problem on the first test, and every one from my class but one got it, and everyone from the other class but one did not more later, cal Chris Landauer Aerospace Integration Science Center The Aerospace Corporation cal@aero.org