Here's some thoughts I've had in relation to the beginning of the book and the first lesson…

Who is Harold Jacobs? I've seen lots and lots of textbooks, and this is so delightfully different from all the rest. So I wanted to tell you a bit about the author. But I googled and looked him up in wikipedia, and I didn't find anything. (Does anyone have better searching skills than me?)

Song. The foreword to the 1st edition mentions the `New Math' of the 60's (not well done) and Tom Lehrer's song about it (very well done).

The Introduction (1st edition) has two puzzles you'll want to try. One has 8 messages to figure out. The other comes from a Babylonian tablet.

Graph paper. The first two lessons really go together, so let's work on them as a unit, and see how long it takes us. Get your graph paper out, you'll be using it to picture a ball bouncing off the sides of a billiard table. (Here's some graph paper, or you could do this online, actually.)

Two physics thoughts. #1: I might be nit-picking, but "we will assume the ball always stops when it comes to a corner" seems misleading, because it doesn't. Maybe "let's pretend the ball always stops …" would have been better? (Or he could have put corner pockets in…) #2: This part is true: "when the ball strikes the cushion (side), it rebounds from it at the same angle". But why is it true? (Is that a physics question or a math question?) I don't have a good way to explain that, does anyone else?

Jacobs poses 3 questions that occur to him after looking at a few different shapes of table, and suggests that we might have our own questions. If you have other questions that these examples bring to mind, please post them now. His are:
1. Will the ball always end up in a corner?
2. Will it ever end up in the original corner?
3. Can you predict which corner it will end up in before drawing its whole path?

Notation. When we discuss table dimensions, let's always use length (height, up and down) as the 1st dimension and width (across) as the 2nd. The first table shown (1st edition) is 10 by 5 (or 10x5).

Remember. Set III is supposed to be challenging. (If you don't figure them all out on your own, don't worry.) Anything else you'd like before starting?





- Notes by Sue VanHattum