Have you ever wondered why so many plants grow in Fibonacci Numbers? Vi Hart offers a great explanation (with hands-on activities) in these three videos — and she introduces a new species called the *slugcat*, which my daughter thinks is adorable.

## Math Teachers at Play #46

Welcome to the ** Math Teachers At Play** blog carnival — which is not just for math teachers! Here is a smorgasbord of ideas for learning, teaching, and playing around with math from preschool to pre-college. Some articles were submitted by their authors, others were drawn from the immense backlog in my blog reader. If you like to learn new things, you are sure to find something of interest.

## Living Books for Math

A child’s intercourse must always be with good books, the best that we can find… We must put into their hands the sources which we must needs use for ourselves, the best books of the best writers.

…

For the mind is capable of dealing with only one kind of food; it lives, grows and is nourished upon ideas only; mere information is to it as a meal of sawdust to the body.

Princess Kitten and I took a longer than usual holiday break from homeschooling, but now I’m in plan-for-the-new-semester mode. I hope to include more living math in our schedule, so I decided to illustrate this edition of the MTaP carnival with a few of my favorite living math books. I’d love to hear more living book suggestions in the comments!

If you click on a book cover, the links take you to Amazon.com, where you can read reviews and other details (and where I earn a small affiliate commission if you actually buy the book), but all of these books should be available through your public library or via inter-library loan.

*Let the mathematical fun begin… *

## 2012 Mathematics Game

*photo by Creativity103 via flickr*

For our homeschool, January is the time to assess our progress and make a few New Semester’s Resolutions. This year, we resolve to challenge ourselves to more math puzzles. Would you like to join us? Pump up your mental muscles with the ** 2012 Mathematics Game**!

## Rules of the Game

Use the digits in the year 2012 to write mathematical expressions for the counting numbers 1 through 100.

- You must use all four digits. You may not use any other numbers.
- You may use +, -, x, ÷, sqrt (square root), ^ (raise to a power), ! (factorial), and parentheses, brackets, or other grouping symbols.
- You may use a decimal point to create numbers such as .2, .01, etc.
- You may create multi-digit numbers such as 10 or 202, but we prefer solutions that avoid them.

Bonus Rules

You may use the overhead-bar (vinculum), dots, or brackets to mark a repeating decimal.You may use multifactorials:

n!! = a double factorial = the product of all integers from 1 tonthat have the same parity (odd or even) asn.n!!! = a triple factorial = the product of all integers from 1 tonthat are equal tonmod 3

[Note to teachers:Math Forum modified their rules to allow double factorials, but as far as I know, they do not allow repeating decimals or triple factorials.]