Tính nhanh a) =5/11 + (-6/11 +2) b) (-1/32 + 1/2) + -15/32

* Hướng dẫn giải

a) $\frac{-5}{11}+\left(\frac{-6}{11}+2\right)=\left(\frac{-5}{11}+\frac{-6}{11}\right)+2=-1+2=1$

b) $\left(\frac{-1}{32}+\frac{1}{2}\right)+\frac{-15}{32}=\left(\frac{-1}{32}+\frac{-15}{32}\right)+\frac{1}{2}=\frac{-1}{2}+\frac{1}{2}=0$