The order of the matrix is defined as m×n , whose product is given as mn . To find all the possible orders of a matrix having 18 elements, we have to find the all the ordered pairs of natural numbers which gives the product of 18 .
The ordered pairs of rows and columns to get 18 elements are: ( 1,18 ) , ( 18,1 ) , ( 2,9 ) , ( 9,2 ) , ( 3,6 ) and ( 6,3 ) .
Hence, the possible orders of a matrix having 18 elements are 1×18 , 18×1 , 2×9 , 9×2 , 3×6 and 6×3 .
If the matrix has 5 elements, the possible ordered pairs of natural numbers are: ( 1,5 ) and ( 5,1 ) .
Thus, the possible order of a matrix having 5 elements are 1×5 and 5×1 .