Fifty Years of Math (in the USA)

Last week I purchased a burger at Burger King for $1.58. The counter girl took my $2 and I went digging for change and pulled out 8 cents from my pocket and gave it to her. She stood there, holding the nickel and 3 pennies, while looking at the screen on her register. I sensed her discomfort and tried to tell her to just give me 2 quarters, but she hailed the manager for help. While he tried to explain the transaction to her, she stood there and cried.

Why do I tell you this? Because of the evolution in math since the 1950's:

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

2. Teaching Math in 1960s:
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?

3. Teaching Math in 1970s:
A logger sells a truckload of lumber for $100. His cost of production is $80. Did he make a profit?

4. Teaching Math in 1980s:
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.

5. Teaching Math in 1990s:
A logger cuts down a beautiful forest because he is selfish and inconsiderate and cares nothing for the habitat of animals or the preservation of our woodlands. He does this so he can make a profit of $20. What do you think of this way of making a living? Topic for class participation after answering the question: How did the birds and squirrels feel as the logger cut down their homes? (There are no wrong answers, and if you feel like crying, it's ok.)

6. Math in 2009:
Un hachero vende una carretada de maderapara $100. El costo de la producciones es $80. Cuanto dinero ha hecho?