\[2\frac{1}{6} + \left( - 2\frac{1}{4} + \left( - 3\frac{3}{5} \right) \right) =\]
\[= 2\frac{1}{6} - \left( 2\frac{5}{20} + 3\frac{12}{20} \right) =\]
\[= 2\frac{1}{6} - 5\frac{17}{20} =\]
\[= - \left( 5\frac{51}{60} - 2\frac{10}{60} \right) = - 3\frac{41}{60}\]