$A$; 5$\frac{2}{7}$ . $\frac{8}{11}$ + 5$\frac{2}{7}$ . $\frac{5}{11}$ - 5$\frac{2}{7}$ . $\frac{2}{11}$
$B$; $\frac{8}{12.13}$ + $\frac{8}{13.14}$ + ... + $\frac{9}{99.100}$
Loga
Sinh Học lớp 12
