Să se calculeze $A+B$ în cazurile (în care are sens):
a) $A=\left(\begin{array}{r}1 \\ -2 \\ 3\end{array}\right), B=\left(\begin{array}{r}3 \\ 4 \\ -5\end{array}\right)$
$A=\left(\begin{array}{rr}1 & -3 \\ 0 & 4\end{array}\right), B=\left(\begin{array}{rr}2 & 4 \\ -5 & -3\end{array}\right) ;$ c) $A=\left(\begin{array}{rrr}1 & -1 & 2 \\ 0 & 3 & 4\end{array}\right), B=\left(\begin{array}{ll}3 & 1 \\ 2 & 0\end{array}\right)$; d) $A=\left(\begin{array}{rrr}1+i & -i & 3 i \\ 0 & 2 i & 1\end{array}\right), B=\left(\begin{array}{rrr}-1-3 i & 2+i & 1 \\ i & 1+i & -i\end{array}\right) ;$ e) $A=\left(\begin{array}{rrr}1 & -2 & 3 \\ 4 & -5 & 6\end{array}\right), B=\left(\begin{array}{rr}1 & 2 \\ 3 & 4 \\ 5 & 6\end{array}\right)$;

f) $A=\left(\begin{array}{lll}1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9\end{array}\right), B=\left(\begin{array}{lll}9 & 8 & 7 \\ 6 & 5 & 4 \\ 3 & 2 & 1\end{array}\right)$