This is the third post for the Year in Review Series. The posts below are the most popular mathematics posts for the year 2012.

**The Most Popular Mathematics Posts**

- Introduction to Geometric Construction
- Origami and its Surprising and Stunning Applications
- 4 Common Errors in Calculating Expressions with Exponents
- Set: Terminologies, Notations, and Operations
- Solving Number Problems: Part 1
- The Proof of the Tangent Half Angle Formula
- How many square are there?
- Understanding If-then Statements and Counterexamples
- The Actual Fermat-Pascal Correspondence
- A US President’s Proof of the Pythagorean Theorem
- Introduction to Clock Arithmetic and Modular Systems

**Explore Math and Multimedia**