Câu 4.
a) $A=\left[ (-0,5)-\frac{3}{5}\text{ }\!\!~\!\!\text{ } \right]:(-3)+\frac{1}{3}-\left( -\frac{1}{6}\text{ }\!\!~\!\!\text{ } \right):(-2)$
$=\text{ }\!\!~\!\!\text{ }\left[ -\frac{1}{2}-\text{ }\!\!~\!\!\text{ }\frac{3}{5} \right]:\text{ }\!\!~\!\!\text{ }(-3)+\text{ }\!\!~\!\!\text{ }\frac{1}{3}-\frac{1}{12}$
$=\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\left[ -\frac{5}{10}-\text{ }\!\!~\!\!\text{ }\frac{6}{10} \right]:\text{ }\!\!~\!\!\text{ }(-3)+\text{ }\!\!~\!\!\text{ }\frac{1}{3}-\frac{1}{12}$
$=\text{ }\!\!~\!\!\text{ }\left[ -\frac{11}{10}:\text{ }\!\!~\!\!\text{ }(-3)\text{ }\!\!~\!\!\text{ }+\text{ }\!\!~\!\!\text{ }\frac{1}{3}-\frac{1}{12} \right]$
$=\frac{37}{60}$
b) $B = \left ( \frac{2}{25} -0,036 \right ) : \frac{11}{50}-\left [ \left ( 3\frac{1}{4} - 2\frac{4}{9} \right ) \right ].\frac{9}{29}$
$B = \left ( \frac{20}{250} -\frac{9}{250}\right ) .\frac{50}{11}-\left [ \left ( \frac{13}{4} - \frac{22}{9} \right ) \right ].\frac{9}{29}$
$B = \frac{11}{250} .\frac{50}{11}-\left [ \left ( \frac{117}{36} - \frac{88}{36} \right ) \right ].\frac{9}{29}$
$B = \frac{1}{5} -\frac{29}{36}.\frac{9}{29}$
$B = \frac{1}{5} -\frac{29}{36}.\frac{9}{29}$
$B = \frac{1}{5} - \frac{1}{4}$
$B = \frac{4}{20} - \frac{5}{20}$
$B = -\frac{1}{20}$