1) Thực hiện phép tính nhanh nhất nếu có thể:
a)
\(\dfrac{2}{7}+\dfrac{7}{7}.\dfrac{14}{25}\)
b)
\(\dfrac{6}{7}+\dfrac{5}{7}:5-\dfrac{8}{9}\)
c)
\(\left(\dfrac{-5}{28}+1,75+\dfrac{8}{35}\right):\left(-3\dfrac{9}{20}\right)\)
d)\(70,5-528:\dfrac{15}{2}\)
e)\(\dfrac{-7}{25}.\dfrac{39}{-14}.\dfrac{50}{78}\)