Welcome to the 84th edition of the **Carnival of Mathematics**. The 83rd edition was posted at Teaching Beside Me.

We have a few entries for this edition. Some were submitted via email and some came from my subscriptions. Here are the entries for this edition.

**For the Adventurous Travelers**

**Katie Erika** tours us around the world of Most Mathematically Interesting Buidlings at Tripbase.

**Ivars Peterson** takes us to Geometreks in Boston posted at Mathematical Tourist.

Adventurous you say? **The Physicist** has an intuitive and superb explanation on “How wormholes can be used for time travel?” posted at Ask a Mathematician.

**For the Tech Savvy**

**Colleen Young** shares with us the Top 100 Tools for Learning for 2011 at Mathematics, Learning, and Web 2.0

**Jon Macloone** gives us 10 Tips for Writing Fast Mathematica Code posted at Wolfram Blog.

You may want Quick Graph for iPad, Ipod Touch, and iPhone presented by **William Emeny** at Great Maths Teaching Ideas.

**For Mathematicians**

**Peter Rowlett** shares his Erdos number at My Erdos Number at Travels in a Mathematical World. He also shares gave a link about a lecture on the uses of mathematics in fiction at the Institute of Maths and Its Applications.

To those who love challenge, why not solve **Sol Lederman**‘s challenging 1111… puzzle at Wild About Math.

For chess lovers, **John Cook** presents an amazing magic square at A knight’s tour magic square posted at The Endeavour.

**For Math Teachers**

**Bogusia Gierus** shares tips on How to teach kids long subtraction with borrowing at Nucleus Learning.

**Whit Ford** presents a strategy in multiplying polynomials in Multiplying Polynomials and FFT posted at Learning and Teaching Mathematics.

**Erlina Ronda** presents a guest post about application of differentiation in parametric context posted at Mathematics for Teaching.

**Kristi Grande** gives her insights on how to ask Questions that Cultivate Mathematical Thinking at Love of Learning Services.

And that rounds up this edition of this blog carnival, I hope you enjoyed reading. There is no schedule for the next Carnival of Math yet, so if you are interested to host, you can contact Michael Croucher.

For those who love to read about math and math teaching, you may want to check out these carnival links:

- Math and Multimedia Carnival 17
- Math Teachers at Play 44
- Carnival of Mathematics 82
- List of Math and Multimedia Carnivals

If you also want to host the **Math and Multimedia Carnival**, please email me at mathandmultimedia@gmail.com.