In[]:=
a={{a11,a12},{a21,a22}}//MatrixForm;b={{b11,b12},{b21,b22}}//Grid;c={{c11,c12},{c21,c22}}//MatrixForm;
In[]:=
a.b.c
Out[]=
.
.
a11 | a12 |
a21 | a22 |
b11 | b12 |
b21 | b22 |
c11 | c12 |
c21 | c22 |
In[]:=
First[a].First[b].First[c]
Out[]=
{{(a11b11+a12b21)c11+(a11b12+a12b22)c21,(a11b11+a12b21)c12+(a11b12+a12b22)c22},{(a21b11+a22b21)c11+(a21b12+a22b22)c21,(a21b11+a22b21)c12+(a21b12+a22b22)c22}}