**So, this matrix...**

**has 2 rows and 3 columns.He's called a 2 x 3 matrix.**

**That's read "a 2 by 3 matrix" and that's NOT a multiplication sign!**

**What's the size of this matrix?**

**3 rows and 2 columns...This is a 3 x 2 matrix.**

*** A 2 x 3 matrix and a 3 x 2 matrix are definitely different sizes!**

**This guy is a 2 x 2 matrix:**

**He's a square matrix.**

**We'll be able to do some special things with square matrices that we won't be able to do with other sizes. (For example, we can only take determinants of square matrices.)**