A Teaching Style That Adds Up

By David J. Hoff

Paterson, N.J.

William Jackson begins class at 12:20 p.m. by posting a cartoon drawing of two rabbits on the chalkboard.

Before he tells his 8th graders why that picture will help illustrate their current lesson, Jackson reminds them of the problem they solved the day before. If someone is paid one penny per day for a job and that wage doubles every day, then 20 days later, the person will be making more than $5,000 a day.

That's the power of exponential growth, he says. Today, he tells his students that they will learn a different method of growth, known as the Fibonacci sequence. And the rate at which rabbits reproduce will play a significant...