Therefore, addition of A and B is defined
and is given by
2
3
1
5
1 1
2
3
1
5
0
A+B
1
1
2
2
3
3
0
0
6
2
2




+
+
−
+
+




=
=




−
+
+








ANote
1 We emphasise that if A and B are not of the same order, then A + B is not
defined For example if 
2
3
A
1
0


= 



, 
1
2
3
B
,
1
0
1


= 



 then A + B is not defined 2