26 December, 2014
Volume 19 No. 52
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In This Issue

Math Forum Online PD Courses

Math Girls Talk About Trigonometry

Foldable Calendar Polyhedral Models


Online PD

Orientation Sessions

Problem Based Learning Courses

Graduate Credit:
Mathematics Teaching and Learning Certificate

Master's Degree


Math Forum Online PD Courses


Our next professional development courses start soon:

To see what teachers have said about past courses upon completing them, check out


The only technical requirements are a web browser and Internet access.

Registrations begin closing Thursday, 8 January, 2015.

PoW taking place: math problem-solving moment of the week

"First I see that it's like a connect-the-dots. It has an order but the answer is not always right next to the previous number. I started by drawing a table.... I found them all out, but it doesn't answer the question. To find the answer ..."
- Eli, highlighted in the FunPoW's Latest Solution

Math Girls Talk About Trigonometry


Bento Books has published the third volume in its Math Girls spinoff series, Math Girls Talk About...

Math Girls Talk About Trigonometry explores a variety of fun and informative topics in trigonometry. Check out the first chapter, full table of contents, and index in this sample download:


This new book ranges from basics like defining the sine function to less frequently seen topics like Lissajous curves. It consists of five chapters, each with review problems and answers:

  • Round Triangles
  • Back and Forth
  • Around and Around
  • Calculating Pi
  • Addition Formulas

As with the first two volumes from this series, the math topics in Math Girls Talk About Trigonometry arise out of conversations among the characters from the young adult novel Mathematical Girls — also by author Hiroshi Yuki — the Japanese language version of which has already gone through some twenty printings.

For more of Bento Books' publications, first featured in these pages three years ago, check out


Now taking place: math education conversation of the day

"Given a 3-frequency geodesic sphere (icosa-based, ominitriangulated), how many triangular facets does it have, and how many edges and vertexes? We just need to plug in the 3 to get V (number of vertexes), subtract 2 to get N, then the ratio N:F:E is 1:2:3, so we're done. But how many sixth graders even know that? Too much algebra?"
- Kirby, posted to the math-teach discussion

Foldable Calendar Polyhedral Models


Want a 2015 calendar to ring in the new year mathematically? Or a timely manipulative to engage your geometry students? Or a last-minute handmade gift for the geek-who-has-everything? Download a polyhedron net and fold up your own three-dimensional, 365-day calendar!

British publishers Cleave Books offer these 3-D models formatted to print out on standard 8.5" × 11" paper:

  • cones
  • rhombic prisms
  • triangular prisms
  • pentagonal antiprisms
  • tetrahedra
  • right pyramids
  • oblique pyramids
  • octahedra
  • rhombohedra
  • delta-dodecahedra
  • triangular prisms
  • hexagonal prisms
  • tetrahedra
  • flexi-tetrahedra


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