a.1/2 x (4/3+2/5) x (8/9+16/5) b.1/5 : 1/10 x (6/5-9/4) c.1/7 : 5/14 - 3/2 x (1/6-7/12) ...
Đọc tiếp
a.1/2 x (4/3+2/5) x (8/9+16/5) b.1/5 : 1/10 x (6/5-9/4) c.1/7 : 5/14 - 3/2 x (1/6-7/12) d.2/1.3 + 6/3.5 + 6/5.7 + ... + 6/99.100
a. \(\frac{1}{2}.\left(\frac{4}{3}+\frac{2}{5}\right).\left(\frac{8}{9}+\frac{16}{5}\right)\)
\(=\frac{1}{2}.\frac{26}{15}.\frac{184}{45}\)
\(=\frac{13}{15}.\frac{184}{45}\)
\(=\frac{2392}{675}\)
b. \(\frac{1}{5}:\frac{1}{10}.\left(\frac{6}{5}-\frac{9}{4}\right)\)
\(=\frac{1}{5}.10.\left(-\frac{21}{10}\right)\)
\(=2.\left(-\frac{21}{20}\right)\)
\(=-\frac{21}{10}\)
c. \(\frac{1}{7}:\frac{5}{14}-\frac{3}{2}.\left(\frac{1}{6}-\frac{7}{12}\right)\)
\(=\frac{1}{7}.\frac{14}{5}-\frac{3}{2}.\left(-\frac{5}{12}\right)\)
\(=\frac{2}{5}-\left(-\frac{5}{8}\right)\)
\(=\frac{49}{60}\)