Question: Matrix multiplication

restart;
with(Student[LinearAlgebra]);
a := Matrix(2, 2, [[1, 2], [3, 4]]);
                               [1  2]
                          a := [    ]
                               [3  4]
b := Matrix(2, 2, [[2, 4], [6, 2]]);
                               [2  4]
                          b := [    ]
                               [6  2]
c := multiply(a, b);
                              /[1  2]  [2  4]\
                 c := multiply|[    ], [    ]|
                              \[3  4]  [6  2]/
evalm(c);
           [        /   [2  4]\          /   [2  4]\]
           [multiply|1, [    ]|  multiply|2, [    ]|]
           [        \   [6  2]/          \   [6  2]/]
           [                                        ]
           [        /   [2  4]\          /   [2  4]\]
           [multiply|3, [    ]|  multiply|4, [    ]|]
           [        \   [6  2]/          \   [6  2]/]