I’m re-reading *Thinking Mathematically*, an assigned book from a math course I took years ago in Portland. I was teaching science at the time but signed up anyway because I’ve always loved math.

*Thinking* is still so good and resonates much more now that I’ve been teaching mathematics.

In the Introduction, under “How to use this book effectively!”:

Recalcitrant questions which resist resolution should not be permitted to produce disappointment. A great deal more can be learned from an unsuccessful attempt than from a question which is quickly resolved, provided you think about it earnestly, make use of techniques suggested in the book, and reflect on what you have done. Answers are irrelevant to the main purpose of this book. The important thing is to experience the process being discussed.

… our approach rests on five important assumptions:

Youcan think mathematically- Mathematical thinking can be
improvedby practice and reflection- Mathematical thinking is
provokedby contradiction, tension and surprise- Mathematical thinking is
supportedby an atmosphere of questioning, challenging and reflecting- Mathematical thinking helps in
understandingyourself and the world

These assumptions need to live in our classrooms.

The problems in *Thinking* are mostly brief and simply stated — yet each one has the potential to make you linger a bit longer because you want to savor your own thinking. Not even productive struggle, this is sweet struggle.

How many rectangles are there on a chessboard? [Page 43]

I have just run out of envelopes. How should I make myself one? [Page 35]

A certain village in Jacobean times had all the valuables locked in a chest in the church. The chest had a number of locks on it, each with its own individual and distinct key. The aim of the village was to ensure that any three people in the village would amongst them have enough keys to open the chest, but no two people would be able to. How many locks are required, and how many keys? [Page 176]

I’m finding out that the 2nd Edition came out in 2010. Amazon does not have it in stock currently, but when it does become available, we can *rent* it for $54.77 or buy it new for $91.29. *What??*

## 8 Comments