Giá trị biểu thức \(\dfrac{2}{5}+\left(\dfrac{-4}{3}\right)+\left(\dfrac{-1}{2}\right)\) là
\(-\dfrac{33}{30}.\)\(\dfrac{31}{30}.\)\(\dfrac{43}{30}.\)\(-\dfrac{43}{30}.\)Hướng dẫn giải:\(\dfrac{2}{5}+\left(\dfrac{-4}{3}\right)+\left(\dfrac{-1}{2}\right)=\dfrac{12}{30}+\left(\dfrac{-40}{30}\right)+\left(\dfrac{-15}{30}\right)=\dfrac{12-40-15}{30}=-\dfrac{43}{30}.\)
