Welcome to the 20th edition of the **Mathematics and Multimedia Blog Carnival**. Here are the posts I have collected this month — some from the Blog Carnival site and some from my RSS feed.

Before we begin a carnival, let’s have some trivia about the number 20.

- The number of sectors in a dartboard.
- The atomic number of calcium.
- It is the smallest primitive abundant number
- The number of faces of an icosahedron
- Can be written as the sum of the three Fibonacci numbers: 13 + 5 + 2

Math and Multimedia Blog Carnival 20 via GeoGebra Applet Central http://t.co/nznczBn5 via @AddThis