Math Teachers at Play #81 via Life Through A Mathematician’s Eyes

[Featured Image (above) by Math Giraffe, and Math Goggles image (right) by Moebius Noodles — two great posts from this month’s carnival.]
Number sense, measurement, place value, functions, calculus for kids, Christmas math activities, art, and much more — check out the December math education blog carnival:
Math Teachers at Play (MTaP) Blog Carnival #81
Welcome to the 81st edition of Math Teachers at Play (MTaP) Blog Carnival. I am extremely exited to host this post in my favorite month of the year, December…
Understanding 81: An interesting fact is that 81 is a tribonacci number (sounds a lot like Fibonacci) – the sequence of tribonacci numbers start with 3 predetermined terms (0,0,1) and each term afterwards is the sum of the preceding 3 terms. Thus the sequence starts like this: 0,0,1,1,2,4,7,13,24,44,81,… (you can go further if you want to see how fast the numbers go).
Now the maths posts…
Join My Mailing List for Math Tips and Book Updates

Learning is a lifelong adventure.
Are you looking for playful ways to help your children learn math? Now you can get math tips and activity ideas by email, as well as find out when I put out a new book or revise an old one.
I hope to send out a “Math Snack” (no-preparation math activity idea) at least once a month. In the meantime, your sign-up bonuses include a 4-page article on solving word problems and a pre-publication peek at my new Math You Can Play book series of games for preschool to prealgebra.
Free This Weekend
Our Christmas gift to you: my daughter’s fantasy adventure Banished will be FREE for Kindle on Amazon.com this weekend only, December 11-15.
I don’t know whether the other Amazons (UK, CA, AU, IN, etc.) will also run the sale, but I hope so.
As I type, the paperback edition is also on sale at a 10% discount, though we have no control over how long Amazon will be offering that price. Banished is part of the Kindle Matchbook program, so if you buy a copy of the paperback, you can get the ebook for free — even after our weekend sale runs out.
Read an excerpt: the first four chapters of Banished
Don’t have a Kindle? You can get a Kindle app that will let you read Teresa’s book on almost any device.
Watch for Upcoming Books
The second book in The Riddled Stone series is scheduled for publication in Spring 2015, and so are the first two volumes of my Math You Can Play series. If you want a head’s-up when these books arrive, be sure to join my Tabletop Academy Press Updates email list:
December Advent Math from Nrich

[Feature photo (above) by Austin Kirk via Flickr (CC BY 2.0).]
Click on the pictures below to explore a mathy Advent Calendar with a new game, activity, or challenge puzzle for each day during the run-up to Christmas. Enjoy!