c) -7/12 .3/8 + -7/12 . 5/8 + 1 7/12

* Hướng dẫn giải

$\begin{array}{l}\mathrm{c}) \frac{-7}{12}.\frac{3}{8}+\frac{-7}{12}.\frac{5}{8}+1\frac{7}{12}\\ =\frac{-7}{12}.\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{12.1+7}{12}\\ =\frac{-7}{12}.\frac{8}{8}+\frac{19}{12}\\ =\frac{-7}{12}+\frac{19}{12}\\ =\frac{12}{12}\\ =1\end{array}$