Find the number of ways to distribute 10 students into lab partners

$\eqalign{\frac{{\left( {\begin{array}{*{20}{c}} {10}\\ 2 \end{array}} \right)\left( {\begin{array}{*{20}{c}} 8\\ 2 \end{array}} \right)\left( {\begin{array}{*{20}{c}} 6\\ 2 \end{array}} \right)\left( {\begin{array}{*{20}{c}} 4\\ 2 \end{array}} \right)}}{{5!}} = 945}$