Here is a 4X4 matrix randomly generated and between 0 and 9 :

Refresh to have a new matrix

7 4 7 4
7 2 0 7
5 7 0 3
9 7 0 8


The average of the first row is 5.5
The average of the second row is 4
The average of the third row is 3.75
The average of the fourth row is 6

The average of the first column is 7
The average of the second column is 5
The average of the third column is 1.75
The average of the fourth column is 5.5