You’re absolutely right. And this is why kids have so much trouble with MATH in upper grades, because they don’t teach them ARITHMETIC in the lower grades!
The New, New Math
I purchased a burger at Burger King for $1.58. The counter girl
took my $2 and I was digging for my change when 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:
1. Teaching Math In 1960s (when I was in school)
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 1970s
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 1980s
A logger sells a truckload of lumber for $100. His cost of
production is $80. Did he make a profit ? Yes or No
4. Teaching Math In 1990s
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 2000s
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 2010
Un hachero vende una carretada de maderapara $100. El costo de la
producciones es $80. Cuanto dinero ha hecho?