I don't know whether this account is true or not, but it certainly gave me cause to snort a bit (in the "je ris par peur d'en finir a pleurer" sense):
Last week 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?
Please read more about the "history of teaching math":
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 sells a truckload of lumber for $100. His cost of production is $80. Did he make a profit?
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 after answering the question: How did the forest birds and squirrels feel as the logger cut down the trees? (There are no wrong answers . )
Teaching Math In 2005
El hachero vende un camion carga por $100. La cuesta de production es...
Actually, something similar happened to us in a restaurant in Northern Maine last summer. A new cashier got very clearly flustered when I tried to help her with the math involved in paying the bill. She ended up abandoning me for the kitchen. A few minutes later, the owner came out to give me my change - told me next time to not be so harsh, the girl was new, etc. (Honestly didn't realize that trying to be helpful was harsh or critical). Shrugged, took my money, left.