Evolution of math

The Evolution of Math in the United States
Last week I purchased a burger and fries at McDonalds for $3.58.
The counter girl took my $4.00 and I pulled 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 two 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 teaching math since the 1960s...
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Teaching Math In 1960_
A logger sells a truckload of lumber for $100. His cost of
production is 4/5 of the price. What is his profit?
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Teaching Math In 1970_
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 1980_
A logger sells a truckload of lumber for $100. His cost of
production is $80. Did he make a profit?

Teaching Math In 1990_
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 2000_
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.)

Teaching Math In 2006_
Un ranchero vende una carretera de maderapara $100. El cuesto de la
produccion era $80. Cuantos tortillas se puede comprar?