アメリカのBobby Hanson先生のCalculusにはとても興味深く学ぶKidsである。何故か？Kidsを満足させる何かがあるからなのであろう。
math.utah.edu/~bobby/2210/HW.pdf
Calculus III Homework. Bobby Hanson ... means that you could miss one assignment, and still possibly score 100% on the homework. Equivalently, ... (a) Give a range of daily high temperatures for Arizona, New York, California, and Utah.