mathematical term for a rectangular

array of numbers.

A matrix is said to be an mxn (read "m by n") matrix if it has m

rows and n

columns. Ie. A 4x4 matrix looks like this:

| 1 2 3 4 |

| 2 2 2 2 |

| 3 5 3 3 |

| 4 4 4 4 |

Each entry in the matrix is denoted as a_i,j where i is the row number and j is the column number

Ie. in the example 4x4 matrix the a_3,2 entry is equal to 5