Cho \(M = \dfrac{{17}}{5}.\dfrac{{ - 31}}{{125}}.\dfrac{1}{2}.\dfrac{{10}}{{17}}.{\left( {\dfrac{{ - 1}}{2}} \right)^3}\)  và \(N = \left( {\dfrac{{17}}{{28}} + \dfrac{{28}}{{29}} - \dfrac{{19}}{{30}} - \dfrac{{20}}{{31}}} \right).\left( {\dfrac{{ - 5}}{{12}} + \dfrac{1}{4} + \dfrac{1}{6}} \right)\). Khi đó tổng \(M + N\) bằng

\(M = \dfrac{{17}}{5}.\dfrac{{ - 31}}{{125}}.\dfrac{1}{2}.\dfrac{{10}}{{17}}.{\left( {\dfrac{{ - 1}}{2}} \right)^3}\)

\(M = \dfrac{{17.\left( { - 31} \right).1.10.{{\left( { - 1} \right)}^3}}}{{{{5.125.2.17.2}^3}}}\)

\(M = \dfrac{{ - 31.\left( { - 1} \right)}}{{{{125.2}^3}}}\)

\(M = \dfrac{{31}}{{1000}}\)

\(N = \left( {\dfrac{{17}}{{28}} + \dfrac{{28}}{{29}} - \dfrac{{19}}{{30}} - \dfrac{{20}}{{31}}} \right).\left( {\dfrac{{ - 5}}{{12}} + \dfrac{1}{4} + \dfrac{1}{6}} \right)\)

\(N = \left( {\dfrac{{17}}{{28}} + \dfrac{{28}}{{29}} - \dfrac{{19}}{{30}} - \dfrac{{20}}{{31}}} \right).\left( {\dfrac{{ - 5}}{{12}} + \dfrac{3}{{12}} + \dfrac{2}{{12}}} \right)\)

\(N = \left( {\dfrac{{17}}{{28}} + \dfrac{{28}}{{29}} - \dfrac{{19}}{{30}} - \dfrac{{20}}{{31}}} \right).0\)

\(N = 0\)

Vậy \(M + N = \dfrac{{31}}{{1000}} + 0 = \dfrac{{31}}{{1000}}\)