Thực hiện phép tính: a) -1/10 + 3/5 + -1/2 b) (3/8 + -3/4 + 7/12) : 5/6 + 1/2

* Hướng dẫn giải

a) $\frac{-1}{10}+\frac{3}{5}+\frac{-1}{2}=\frac{-1}{10}+\frac{6}{10}+\frac{-5}{10}=0$

b) 

$\begin{array}{l}\left(\frac{3}{8}+\frac{-3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\\ =\left(\frac{9}{24}+\frac{-18}{24}+\frac{14}{24}\right):\frac{5}{6}+\frac{1}{2}\\ =\frac{5}{24}\cdot \frac{6}{5}+\frac{1}{2}\\ =\frac{1}{4}+\frac{1}{2}\\ =\frac{3}{4}\end{array}$