Câu 1:
\(-\dfrac{5}{12}+\dfrac{3}{8}-\dfrac{1}{2}\\ =-\dfrac{20}{56}+\dfrac{21}{56}-\dfrac{28}{56}\\ =-\dfrac{27}{56}\)
Câu 2:
\(\dfrac{1}{4}+\dfrac{7}{12}-\dfrac{6}{13}-\dfrac{7}{8}\\ =\dfrac{78}{312}+\dfrac{182}{312}-\dfrac{144}{312}-\dfrac{273}{312}\\ =-\dfrac{157}{312}\)