Teaching Math in 1950:
A logger sells a truckload of lumber for $100. His cost of production is 4/5 of the price. What is his profit?

Teaching Math in 1960:
A logger sells a truckload of lumber for $100. His cost of production is 4/5 of the price, or $80. What is his profit?

Teaching Math in 1970:
A logger exchanges a set "L" of lumber for a set "M" of money. The cardinality of set "M" is 100. Each element is worth one dollar. The set "C", the cost of production contains 20 fewer points than set What is the cardinality of the set "P" of profits?

Teaching Math 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.

Teaching Math in 1990:
By cutting down beautiful forest trees, the 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 as the logger cut down the trees? There are no wrong answers.

Teaching Math in 1993:
By laying off 402 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.

Teaching Math in 1997:
A company outsources all of its loggers. They save on benefits and when demand for their product is down the logging work force can easily be cut back. The average logger employed by the company earned $50,000, had 3 weeks vacation, received a nice retirement plan and medical insurance. The contracted logger charges $50 an hour. Was outsourcing a good move?

Teaching Math in the new millennium:
A logging company exports its wood-finishing jobs to its Indonesian subsidiary and lays off the corresponding half of its US workers (the higher-paid half). It clear-cuts 95% of the forest, leaving the rest for the spotted owl, and lays off all its remaining US workers. It tells the workers that the spotted owl is responsible for the absence of fellable trees and lobbies Congress for exemption from the Endangered Species Act. Congress instead exempts the company from all federal regulation. What is the return on investment of the lobbying?

I am.
is the shortest complete sentence in the English language.