Cho A= (1/4+ -5/13) + ( 2/11+ -8/13+ 3/4). Chọn câu đúng:

* Hướng dẫn giải

$A=\left(\frac{1}{4}+\frac{-5}{13}\right)+\left(\frac{2}{11}+\frac{-8}{13}+\frac{3}{4}\right)$

$A=\frac{1}{4}+\frac{-5}{13}+\frac{2}{11}+\frac{-8}{13}+\frac{3}{4}$

$A=\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{-5}{13}+\frac{-8}{13}\right)+\frac{2}{11}$

$A=1+\left(-1\right)+\frac{2}{11}$

$A=\frac{2}{11}$