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?

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?

In 1970:
A logger exchanges a set “L” of logs for a set “M” of money.  The cardinality of set “M” is 100.  Each element is worth one dollar.  Make 100 dots representing the elements of the set “M”.  The set “C”, the cost of production, contains 20 fewer points than set “M”. 
Represent the set “C” as a subset of set “M” and answer the following question: What is the cardinality of the set “P” of profits?

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.

In 1990:
By cutting down beautiful 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 little birds and animals feel as the logger cut down the trees?  There are no wrong answers.

In 2000:
A logger sells a truckload of lumber for $100.  His cost of production is $120. 
How did Arthur Andersen determine that his profit margin was $60?

In 2010:
El hachero vende un camion carga por 100 pesos . . .