Teaching Maths 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 a living? (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.