a) $(-0.5)-(-1+\frac{2}{3})/1.5+(\frac{-1}{4})=(\frac{-1}{2})-(\frac{-1}{3})\times\frac{2}{3}+(\frac{-1}{4})=(\frac{-1}{2})+\frac{2}{9}+(\frac{-1}{4})=\frac{-19}{36}$
b) $[(\frac{-7}{8}/\frac{21}{16}]-\frac{5}{3}\times(\frac{1}{3}-\frac{7}{10})=[(\frac{-7}{8})\times\frac{16}{21}]-\frac{5}{3}\times(\frac{-11}{10})=(\frac{-2}{3})+\frac{11}{6}=\frac{7}{6}$
c) $[(\frac{-2}{3}+\frac{3}{4}]^{2}\times\frac{12}{5}-\frac{1}{5}=(\frac{1}{12})^{2}\times\frac{12}{5}-\frac{1}{5}=\frac{1}{60}-\frac{1}{5}=\frac{-11}{60}$
d) $(\frac{1}{25}-0.4)^{2}/\frac{9}{125}-[(1\frac{1}{3}-\frac{2}{5})\times\frac{3}{7}]=(\frac{-9}{25})^{2}/\frac{9}{125}-(\frac{14}{5}\times\frac{3}{7})=\frac{9}{5}-\frac{2}{5}=\frac{7}{5}$
e) ${3\frac{17}{18}\times[\frac{5}{2}-(\frac{1}{3}+\frac{2}{9}]}/[(\frac{-1}{2})+0.25]^{2}={\frac{71}{18}\times[\frac{5}{2}-\frac{5}{9}]}/(\frac{-1}{4})^{2}=\frac{2485}{324}/\frac{1}{16}=\frac{9940}{81}$