**A math problem in the 60's**

A logger sells a truckload of lumber for $100. His cost of production is four-fifths of this price. What is his profit?

**A math problem in the 70's**

A logger sells a truckload of lumber for $100. His cost of porduction is four-fifths of this price, or $80. What is his profit?

**A math problem in the 70's using New Math**

A logger exchanges a set L of lumber for a set M of money. The cardinality of set M is 100, and each element is worth $1. Make 100 dots representing the elements of set M. The set C of the cost of production contains 20 fewer points than set M, and answer the following question: What is the cardinality of the set P of profits?

**A math problem in the 80's**

A logger sells a truckload of wood for $100. His cost of production is $80, and his profit is $20. Your assignment: underline the number 20.

**A math problem in the 90's**under Outcome Based Education.

By cutting down beautiful forest trees, a logger makes $20. What do you think of this way of living? (Topic for class participation: How did the forest birds and squirrels feel?)