Evaluate $-\frac{3}{16}-\frac{1}{8}$−316−18, writing your answer as a simplified fraction.

Evaluate $\frac{-2}{7}+\frac{8}{21}$−27+821, writing your answer in its simplest form.

Evaluate $\frac{7}{10}+\frac{-3}{5}$710+−35, writing your answer in its simplest form.

Evaluate $-\frac{5}{14}+\frac{-3}{7}$−514+−37, writing your answer in its simplest form.