Tính một cách hợp lí.

$A=\left(-\frac{3}{11}\right)+\frac{11}{8}-\frac{3}{8}+\left(-\frac{8}{11}\right).$

Giải

$$\begin{gathered} A=\left(-\frac{3}{11}\right)+\frac{11}{8}-\frac{3}{8}+\left(-\frac{8}{11}\right) \\ =\left[\left(-\frac{3}{11}\right)+\left(-\frac{8}{11}\right)\right]+\left(\frac{11}{8}-\frac{3}{8}\right) \\ =\frac{(-3)+(-8)}{11}+\frac{11-3}{8} \\ =\frac{-11}{11}+\frac{8}{8} \\ =-1+1 \\ =0 \end{gathered}$$