Đáp án:
$\begin{array}{l}
1)a)16\frac{2}{7}.\left( { - \frac{5}{3}} \right) - 28\frac{2}{7}.\left( {\frac{{ - 5}}{7}} \right) = \frac{{16.7 + 2}}{7}.\left( {\frac{{ - 5}}{3}} \right) - \frac{{28.7 + 2}}{7}.\left( {\frac{{ - 5}}{7}} \right)\\
= \frac{{144}}{7}.\left( {\frac{{ - 5}}{3}} \right) - \frac{{198}}{7}.\left( {\frac{{ - 5}}{7}} \right) = \left( {\frac{{ - 5}}{7}} \right).\left( {48 - \frac{{198}}{7}} \right) = \left( {\frac{{ - 5}}{7}} \right).\frac{{138}}{7} = \frac{{ - 690}}{{49}}\\
b){\left( { - 2} \right)^3}.\left( {\frac{3}{4} - 0,25} \right):\left( {2\frac{1}{4} - 1\frac{1}{6}} \right)\\
= - 8.\left( {\frac{3}{4} - \frac{1}{4}} \right):\left( {\frac{9}{4} - \frac{7}{6}} \right)\\
= - 8.\frac{2}{4}:\frac{{13}}{{12}} = - 4.\frac{{12}}{{13}} = \frac{{ - 48}}{{13}}
\end{array}$
