(A)=q^{k-t}{\left[\begin{matrix} n-k \\ 0 \end{matrix} \right]_{q}}\left( {\left[\begin{matrix} n-t-0 \\ 0 \end{matrix} \right]_{q}}-\frac{0}{q}{\left[\begin{matrix} k-t \\ 0 \end{matrix} \right]_{q}}{\left[\begin{matrix} t+0 \\ 0 \end{matrix} \right]_{q}}\right)\frac{0}{q+0}.$$  