Câu 1. Thực hiện phép tính
a) $\frac{2}{5}+\frac{3}{5}:\left ( -\frac{3}{2} \right )+\frac{1}{2}$
= $\frac{2}{5} + \frac{-2}{5} + \frac{1}{2}$
= $0+ \frac{1}{2}$
= $\frac{1}{2}$
b) $2\frac{1}{3} + \left ( -\frac{1}{3} \right )^{2}-\frac{3}{2}$
= $\frac{7}{3} + \frac{1}{9} -\frac{3}{2}$
= $\frac{21}{9} + \frac{1}{9} -\frac{3}{2}$
= $\frac{22}{9} -\frac{3}{2}$
= $\frac{44}{18} -\frac{27}{18}$
= $\frac{17}{18}$
c) $\left ( \frac{7}{8}-0,25 \right ) : \left ( \frac{5}{6}-0,75 \right )^{2}$
= $\left ( \frac{7}{8}-\frac{1}{4} \right ) : \left ( \frac{5}{6}-\frac{3}{4} \right )^{2}$
= $\left ( \frac{7}{8}-\frac{2}{8} \right ) : \left ( \frac{10}{12}-\frac{9}{12} \right )^{2}$
= $\frac{5}{8} : \frac{1}{144} $
= 90
d) $(-0,75) - \left [ (-2) + \frac{3}{2} \right ]:1,5 + \left ( \frac{-5}{4} \right )$
= $\frac{-3}{4} - \left [ \frac{-4}{2} + \frac{3}{2} \right ]: \frac{3}{2} + \left ( \frac{-5}{4} \right )$
= $\frac{-3}{4} - \left [ \frac{-4}{2} + \frac{3}{2} \right ]: \frac{3}{2} + \left ( \frac{-5}{4} \right )$
= $\frac{-3}{4} + \frac{1}{3} + \left ( \frac{-5}{4} \right )$
= $\frac{-9}{12} + \frac{4}{12} - \frac{15}{12}$
= $\frac{-20}{12}$
= $\frac{-5}{3}$