Sub product()
' Find the product of two matrices C=A*B
' Variables used ...
'   rowsA ... number of rows of A
'   colsA ... number of columns of A = number of rows of B
'   colsB ... number of columns of B
' Instructor: Nam Sun Wang

'Save space to store A, B, C
      Dim A(10, 10), B(10, 10), C(10, 10)

' Specify dimension
      rowsA = 3
      colsA = 3
      rowsB = colsA
      colsB = 2

' Define A
      For i = 1 To rowsA
        For j = 1 To colsA
'         A(1,1)=Cells(3,2)
          A(i, j) = Cells(i + 2, j + 1)
        Next
      Next
 
' Define B
      For i = 1 To rowsB
        For j = 1 To colsB
'         B(1,1)=Cells(3,6)
          B(i, j) = Cells(i + 2, j + 5)
        Next
      Next

' Do the matrix product
      For i = 1 To rowsA
        For j = 1 To colsA
          C(i, j) = 0
          For k = 1 To colsA
            C(i, j) = C(i, j) + A(i, k) * B(k, j) 'summation
          Next k
        Next j
      Next i

' Output C back to the Excel worksheet
      For i = 1 To rowsA
        For j = 1 To colsB
'         Cells(7,2)=C(1,1)
          Cells(i + 6, j + 1) = C(i, j)
        Next
      Next
      
      End Sub