Thực hiện phép tính (tính hợp lí nếu có thể): a) \(\frac{{ - 5}}{8} \cdot \frac{{ - 12}}{{29}} \cdot \frac{8}{{ - 10}} \cdot 2,9.\) b) \(2,35:\left( { - 0,01} \right) + 650 \cdot \left( { -

a) \(\frac{{ - 5}}{8} \cdot \frac{{ - 12}}{{29}} \cdot \frac{8}{{ - 10}} \cdot 2,9\)

\( = \frac{{ - 5}}{8} \cdot \frac{{ - 6 \cdot 2}}{{29}} \cdot \frac{8}{{ - 5 \cdot 2}} \cdot \frac{{29}}{{10}}\)

\( = \frac{{ - 6}}{{10}} =  - \frac{3}{5}.\)

b) \(2,35:\left( { - 0,01} \right) + 650 \cdot \left( { - 0,1} \right)\)

\( =  - 235 - 65\)

\( =  - 300.\)

c) \(\frac{2}{{11}}.\frac{{ - 5}}{4} + \frac{{ - 9}}{{11}}.\frac{5}{4} + 1\frac{3}{4}\)

\( = \frac{2}{{11}} \cdot \frac{{ - 5}}{4} + \frac{9}{{11}} \cdot \frac{{ - 5}}{4} + \frac{7}{4}\)

\( = \frac{{ - 5}}{4} \cdot \left( {\frac{2}{{11}} + \frac{9}{{11}}} \right) + \frac{7}{4}\)

\( = \frac{{ - 5}}{4} \cdot \frac{{11}}{{11}} + \frac{7}{4}\)

\( = \frac{{ - 5}}{4} \cdot 1 + \frac{7}{4}\)

\[ = \frac{{ - 5}}{4} + \frac{7}{4}\]

\[ = \frac{2}{4} = \frac{1}{2}.\]

d) \[{\left( { - 2} \right)^3} \cdot \frac{{ - 1}}{{24}} + \left( {80\%  - 1,2} \right):\frac{2}{{15}}\]

\( = \left( { - 8} \right) \cdot \frac{{ - 1}}{{24}} + \left( {\frac{4}{5} - \frac{6}{5}} \right) \cdot \frac{{15}}{2}\)

\( = \frac{1}{3} + \frac{{ - 2}}{5} \cdot \frac{{15}}{2}\)

\( = \frac{1}{3} + \left( { - 3} \right)\)

\( = \frac{1}{3} + \frac{{ - 9}}{3} = \frac{{ - 8}}{3}.\)