Đáp án:
$\begin{array}{l}
156)\\
\frac{3}{{5.8}} + \frac{{11}}{{8.19}} + \frac{{12}}{{19.31}} + \frac{{70}}{{31.101}} + \frac{{99}}{{101.200}}\\
= \frac{{8 - 5}}{{5.8}} + \frac{{19 - 8}}{{8.19}} + \frac{{31 - 19}}{{19.31}} + \frac{{101 - 31}}{{31.101}} + \frac{{200 - 101}}{{101.200}}\\
= \frac{8}{{5.8}} - \frac{5}{{5.8}} + \frac{{19}}{{8.19}} - \frac{8}{{8.19}} + ... + \frac{{200}}{{101.200}} - \frac{{101}}{{101.200}}\\
= \frac{1}{5} - \frac{1}{8} + \frac{1}{8} - \frac{1}{{19}} + \frac{1}{{19}} - \frac{1}{{31}} + \frac{1}{{31}} - \frac{1}{{101}} + \frac{1}{{101}} - \frac{1}{{200}}\\
= \frac{1}{5} - \frac{1}{{200}}\\
= \frac{{40 - 1}}{{200}}\\
= \frac{{39}}{{200}}
\end{array}$
