Giải thích các bước giải:
\[\begin{array}{l}
a)(\frac{9}{{25}} - 2.18):(3\frac{4}{5} + 0,2) = (\frac{9}{{25}} - 36):(\frac{{19}}{5} + \frac{1}{5}) = \frac{{ - 891}}{{25}}:4 = \frac{{ - 891}}{{100}}\\
b)\frac{3}{8}.19\frac{1}{3} - \frac{3}{8}.33\frac{1}{3} = \frac{3}{8}(19\frac{1}{3} - 33\frac{1}{3}) = \frac{3}{8}.( - 14) = \frac{{ - 21}}{4}\\
c)\frac{{13}}{{25}} + \frac{6}{{41}} - \frac{{38}}{{25}} + \frac{{35}}{{41}} - \frac{1}{2} = (\frac{{13}}{{25}} - \frac{{38}}{{25}}) + (\frac{6}{{41}} + \frac{{35}}{{41}}) - \frac{1}{2} = - 1 + 1 - \frac{1}{2} = \frac{{ - 1}}{2}
\end{array}\]
