# The Joy of X, A guided tour of Math....

2013 June 16
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title: The Joy of X, A guided tour of Math....
author: john
date: 2013-06-16
amazon_asins=0547517653
*/
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###The Joy of X, A guided Tour of Math, from One to Infinity by Steven Strogatz.
Found this book by accident.  An interesting and easy read. So far through a couple chapters and it has been a good review in how to think mathematically without too much reliance on equations.

[[#ENDSUMMARY]]

## From Fish to Infinity

Check out Sesame Street Video called [123 Count with Me](http://www.youtube.com/watch?v=aR2r9MtcTgo) and the [author's article in the NY TImes](http://opinionator.blogs.nytimes.com/2010/01/31/from-fish-to-infinity/).

Did humanity invent numbers? Or discover them?  The dual aspect of numbers.  We event the concept of numbers and then discover the consequences of the concepts.

## Rock Groups

* "A Mathematicians Lament" by Paul Lockhart
* "The housekeeper and the Professor" by Yoko Ogawa

Natural Numbers, Odd, Even, Composite, Prime, Perfect Squares,

The word calculate from Latin calculus, meaning a pebble/stone used for counting

Einstein = one stone

## The enemy of my Enemy

carrying/borrowing

Subtraction introduces the problem of negative numbers
Why a negative times negative is a positive when two wrongs don't make a right!

## Commuting

The commutative law of multiplication.

Maybe we doubt the law because in real life it often matters what you do first.  really?

## Division and Its Discontents

Natural Numbers
Integers
Rational Numbers (fractions: ratios of integers)
Irrational Numbers (decimals that can't be expressed as fractions)
Real Numbers

Most decimal numbers are irrational.  Rational decimals either stop at some point or have a repeating pattern.

* "My Left Foot" true story of Christy Brown

## Location, Location, Location

Introduces us to positional notation using a base. Our system, versus older counting methods. Also introduces base 2.

## The Joy of X
Algebra is basically two things

* Solve for x
* Working with formulas

The length of a hallway is Y measured in yards, and F when measured in feet. Write an equation that relates y to f.

identity formulas.

How to square numbers near 50.  or 100 etc...