Tính nhanh biểu thức A = \(1\dfrac{2}{3}.\dfrac{4}{35}+1\dfrac{2}{3}.\dfrac{17}{35}+\dfrac{5}{3}.\dfrac{14}{35}\).
\(\dfrac{3}{5}.\)\(\dfrac{5}{3}.\)\(\dfrac{1}{5}. \)\(\dfrac{1}{3}.\)Hướng dẫn giải:A = \(1\dfrac{2}{3}.\dfrac{4}{35}+1\dfrac{2}{3}.\dfrac{17}{35}+\dfrac{5}{3}.\dfrac{14}{35}\)
\(=\dfrac{5}{3}.\dfrac{4}{35}+\dfrac{5}{3}.\dfrac{17}{35}+\dfrac{5}{3}.\dfrac{14}{35}\)
\(=\dfrac{5}{3}.\Big(\dfrac{4}{35}+\dfrac{17}{35}+\dfrac{14}{35}\Big)\)
\(=\dfrac{5}{3}.1=\dfrac{5}{3}.\)
