The evolution in teaching math

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. Teaching Math In 2008
Un hachero vende una carretada de maderapara $100. El costo de la
producciones es $80. Cuanto dinero ha hecho?