**Define a matrix**

** **

An ordered array of numbers such as

Is called a matrix. The numbers are called **elements **of the matrix. Matrices (the plural of *matrix*) are named according to the number of **rows **and **columns **they contain. The rows are read horizontally, and the columns are read vertically.

For example, the first row in the preceding matrix is 2 3 4 and the first column is . This matrix is a 2 3 3 (read “two by three”) matrix because it has 2 rows and 3 columns. The number of rows is given first, and then the number of columns.