Relation between Normal Matrix and Identity Matrix

We know that any number remains the same when multiplied by 1.

e.g. :   

Similarly,   any matrix remains the same when multiplied by the identity matrix. 

e.g. :              ;          where ,  A  is a matrix
                                                                                         I   is a identity matrix

Note :  Identity matrix is a square matrix whose diagonal element is 1 and remaining 
             element are zero's .
   
              e.g. :