Two engineers were standing in the park. One had a new bike. The other said, "Nice bike. How much?" The first said, "It was free." The other asked, "Wow, how did you get it for free?" The one with the bike said, "Yesterday a beautiful girl rode up on this bike, took off all her clothes and told me I could have anything I wanted." The other engineer said, "Good move! Her clothes wouldn't have fit you anyway."

TEACHING MATH THROUGH THE DECADES In 1950: A logger sells a truckload of lumber for $100. His cost of production is four-fifths of the price. What is his profit? In 1960: A logger sells a truckload of lumber for $100. His cost of production is four-fifths of the price, or $80. What is his profit? In 1970 (new math): A logger exchanges a set L of lumber for a set M of money. The cardinality of set M is 100, and each element is worth $1.00. Make 100 dots representing the elements of the set M. The set C of the costs of production contains 20 fewer points than set M. Represent the set C as a subset of M, and answer the following question: What is the cardinality of the set p of profits? In 1980: A logger sells a truckload of lumber for $100. His cost of production is $80, and his profit is $20. Your assignment: underline the number 20. In 1990 (outcome-based education): By cutting down beautiful forest trees, a logger makes $20. What do you think of this way of making aliving? (Topic for class participation: How did the forest birds and squirrels feel?) In 2000: By laying off 40% of its loggers, a company improves its stock price from $80 to $100. How much capital gain per share does the CEO make by exercising his stock options at $80? Assume capital gains are no longer taxed, because this encourages investment.