# The Putnam Exam

Math Fans: If you are good at solving math problems, and are not doing anything on Dec 2, 2000 (a Saturday), then the NIU Math Department needs you. On that date, the 2000 Putnam exam will be given at hundreds of universities throughout the country. The exam starts in the morning (9 a.m.) and goes to noon, followed by FREE PIZZA and soda pop at a local establishment. The afternoon session goes from 2 to 5 p.m. The questions require mathematical ingenuity more than regurgitation. In fact, Putnam questions are like the Math Department's Problem of the Month--only you don't have a month to solve them.

Here's a typical problem:  Show that it is impossible to draw a four sided figure in the plane whose four sides and two diagonals are all odd integers. (A 3 by 4 rectangle has integer sides and diagonals, but 4 is not odd.)

Here's another problem:  How many primes among the positive integers, written as usual in base 10, are such that their digits are alternating 1's and 0's, beginning and ending with 1? (For example, 101 is prime, 10101 is not.)