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:

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?

TEACHING MATH IN 2005:

Un hachero vende una carretada de Madera pare $100. ¡El costo de la producción es
$80….