74…seventy-four…LXXIV…setenta y cuatro…soixante-quatorze…siebzig vier…

© Depositphotos.com/stoonn

Regardless of how you say it:

- 74% is the storage density of a volume filled with small spheres. (What’s Special About This Number)
- 74 = 17 + 18 + 19 + 20 (What’s Special About This Number)
- 74 is the atomic number of tungsten. (Wikipedia)
- A seventy-four was a third-rate warship with 74 guns. (Wikipedia)
- A hurricane or typhoon is a system with sustained winds of at least 74 MPH. (Wikipedia)

Welcome to the 74th Edition of the Math Teachers at Play (MTaP) blog carnival.

### Origami

Learn how to make Origami Stars, Tessellation Stars, and Chaotic Stars at Math Munch. I think once your students or children see this, you will find Transforming Ninja Stars littering your house and classroom!

Corner bookmarks would be a fun way to practice origami. Here’s a few sites with instructions for making them: The Cheese Thief, Bloomize, and Split Coast Stampers.

Robert Lang’s TED talk, “The Math and Magic of Origami,” tells us how he made intricate designs with one piece of paper and no cuts. His work is amazing. He also describes how origami has been used in car commercials, to fold telescopes for transport into space, an origami heart stint, and air bag simulation. His website has pictures of his art and links to other origami resources.

© Depositphotos.com/toponium

### Pi

“Pi is a name given to the ratio of the circumference of a circle to the diameter. That means, for any circle, you can divide the circumference (the distance around the circle) by the diameter and always get exactly the same number. It doesn’t matter how big or small the circle is, Pi remains the same. Pi is often written using the symbol and is pronounced “pie”, just like the dessert.” You can read more about Pi at math.com.

Here’s a fun activity to explore other ways to get the number Pi on the calculator from William Wu at Singapore Maths Tuition.

Little Theorems provides his notes on Viete’s formula and how he derived a related formula using methods similar to Viete’s for computing Pi. A high school student interested in Pi might enjoy this post.

### Math Games

Math=Love shares a fun probability bingo game. This game looks fun even for younger students.

Margo’s Math and More shares a great subtraction game for the summer—Beach Bowling Subtraction.

Math Hombre shares a coordinate grid game that also calculates area of rectangles. And all you need is some grid paper and dice.

Miller Pad and Paper has a paper version of Battleship which is perfect for car trips!

### Miscellaneous

Highhill Homeschool shares how they measured the elevation of a hill using a level, two old broom handles, scissors, string, permanent marker, ruler and tape.

Math Missy shares ways to incorporate math language into your student’s life.

“Slowing down for a few weeks eventually helped us to speed up because of the deeper understanding of the topic.” Read how Sandbox to Socrates helped her struggling student move forward.

Let’s Play Math shares a fraction quiz to help us think through fraction rules. Test yourself: How well do you understand these fraction rules?

If you enjoyed this blog carnival, you can view past Math Teachers at Play blog carnivals and submit posts for future editions. You might also be interested in the Carnival of Mathematics.