Bài tập 91 trang 27 SBT Toán 6 Tập 2

\(\begin{array}{l}
M = \frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10.\frac{{19}}{{92}}\\
 = \left( {\frac{8}{3}.\frac{3}{8}} \right).\left( {\frac{2}{5}.10} \right).\frac{{19}}{{92}}\\
 = 1.4.\frac{{19}}{{92}} = \frac{{4.19}}{{92}} = \frac{{19}}{{23}}\\
N = \frac{5}{7}.\frac{5}{{11}} + \frac{5}{7}.\frac{2}{{11}} - \frac{5}{7}.\frac{{14}}{{11}}\\
 = \frac{5}{7}.\left( {\frac{5}{{11}} + \frac{2}{{11}} - \frac{{14}}{{11}}} \right)\\
 = \frac{5}{7}.\frac{{ - 7}}{{11}} = \frac{{ - 5}}{{11}}\\
Q = \left( {\frac{1}{{99}} + \frac{{12}}{{999}} - \frac{{13}}{{9999}}} \right).\left( {\frac{1}{2} - \frac{1}{3} - \frac{1}{6}} \right)\\
 = \left( {\frac{1}{{99}} + \frac{{12}}{{999}} - \frac{{13}}{{9999}}} \right).\left( {\frac{3}{6} + \frac{{ - 2}}{6} + \frac{{ - 1}}{6}} \right)\\
 = \left( {\frac{1}{{99}} + \frac{{12}}{{999}} - \frac{{13}}{{9999}}} \right).0 = 0
\end{array}\)

-- Mod Toán 6 HỌC247