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.

Charlotte Mason
Toward A Philosophy of Education

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, 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…


image via WolframMathWorld

By tradition, we start the carnival with a puzzle in honor of our 46th edition. 46 is a centered triangular number.

  • Study the diagram to see how centered triangular numbers are constructed. Every centered triangular number is equal to 1(mod 3). Can you see why?
  • We start with n=0 for the single dot in the middle, n=1 includes the center + the smallest triangle, etc. Counting in this way, what value of n will have 46 dots?
  • Can you find all the centered triangular numbers less than 100?
  • Every centered triangular number 10 or greater contains three consecutive regular triangular numbers. Draw a few big centered triangles (n>3). Can you outline the three triangular numbers in each sketch?


12 Ways to Get to 11 is more than just a fun counting book. Introduce young children to number bonds and partitions — new ways to look at the world of numbers!


The Man Who Counted features classic mathematical puzzles in an exotic setting, following the fictional adventures of Persian sheep-herder turned mathematician Beremiz as he uses his wits to gain fame, fortune, and a beautiful wife.

  • Gaurav asks, “Do you multiply this way?” My challenge: Don’t memorize this method as a trick, but study until you see why it works. How is it similar to the standard method?


Flatland: A Romance of Many Dimensions, a classic of mathematical fiction, follows the adventures of A. Square as he transcends his assumptions about reality and explores several geometric worlds.


The Language of Mathematics: Making the Invisible Visible (or the earlier version, Mathematics: The Science of Patterns) helps answer the question, “Why do we have to learn this?” If you’ve ever wondered what mathematicians mean when they say math is “beautiful” — read this book!

  • Murray plays around with Biorhythm Graphs: “A bit of fun — a non-scientific application of composite sine curves!”
  • John shares a couple of problems from his preservice high school teachers’ final. How would you fare?


What Is the Name of This Book?: The Riddle of Dracula and Other Logical Puzzles is finally back in print. (And Alice in Puzzle-Land, too. Thank you, Dover Publications!) Try your hand at a few traditional brain teasers, and explore the Island of Knights and Knaves. Can you tell the difference between a sane human and an insane vampire?

  • Gary shares a few puzzles that elementary-age children can understand but adults can enjoy exploring as well: Numberplay: Tanton Wordless.
  • My entry for the carnival is the 2012 Mathematics Game, a terrific puzzle for middle school and beyond.


Martin Gardner inspired many of us to become mathematicians and math teachers. Now our children can enjoy 50 of his best “Mathematical Games” columns in one volume, The Colossal Book of Mathematics: Classic Puzzles, Paradoxes, and Problems. What a treasure!


I love reading math biographies. Fermat’s Enigma: The Epic Quest to Solve the World’s Greatest Mathematical Problem is the “biography” of a math problem. It’s the next book on my library-loan list, and I can’t wait for it to arrive…


That rounds out this edition of the Math Teachers at Play carnival. I hope you enjoyed the ride. The next installment of our carnival will open on February 17 at Math Hombre. If you would like to contribute, please use this handy submission form or email John directly. Posts must be relevant to students or teachers of preschool through precollege mathematics. Old posts are welcome, as long as they haven’t been published in past editions of this carnival.

Past posts and future hosts can be found on our blog carnival index page.

We need more volunteers. Classroom teachers, homeschoolers, unschoolers, or anyone who likes to play around with math (even if the only person you “teach” is yourself) — if you would like to take a turn hosting the Math Teachers at Play blog carnival, please speak up!

7 thoughts on “Math Teachers at Play #46

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.