Đáp án:
$\begin{array}{l}
g){\left( {\dfrac{2}{5}} \right)^2} + 5\dfrac{1}{2}.\left( {4,5 - 2} \right) + \dfrac{{{2^3}}}{{\left( { - 4} \right)}}\\
= \dfrac{4}{{25}} + \dfrac{{11}}{2}.\left( {\dfrac{9}{2} - 2} \right) + \dfrac{8}{{ - 4}}\\
= \dfrac{4}{{25}} + \dfrac{{11}}{2}.\dfrac{5}{2} - 2\\
= \dfrac{4}{{25}} + \dfrac{{55}}{4} - 2\\
= \dfrac{{4.4 + 55.25 - 2.100}}{{100}}\\
= \dfrac{{1191}}{{100}}\\
h)\dfrac{4}{9}.19\dfrac{1}{3} - \dfrac{4}{9}.39\dfrac{1}{3}\\
= \dfrac{4}{9}.\left( {19\dfrac{1}{3} - 39\dfrac{1}{3}} \right)\\
= \dfrac{4}{9}.\left( { - 20\dfrac{1}{3}} \right)\\
= \dfrac{4}{9}.\dfrac{{ - 61}}{3}\\
= \dfrac{{ - 244}}{{27}}\\
i){\left( { - \dfrac{1}{2}} \right)^2}:\dfrac{1}{4} - 2.{\left( { - \dfrac{1}{2}} \right)^2}\\
= \dfrac{1}{4}.4 - 2.\dfrac{1}{4}\\
= 1 - \dfrac{1}{2}\\
= \dfrac{1}{2}
\end{array}$
