Question

Tính nhanh nếu có thể

\(\left(1\dfrac{3}{7}-\dfrac{5}{12}\right):\dfrac{4}{5}-\left(\dfrac{3}{7}-\dfrac{17}{12}\right):\dfrac{4}{5}\)

Answer 1

\(\left(1\dfrac{3}{7}-\dfrac{5}{12}\right):\dfrac{4}{5}-\left(\dfrac{3}{7}-\dfrac{17}{12}\right):\dfrac{4}{5}\)

\(=\left(\dfrac{10}{7}-\dfrac{5}{12}-\dfrac{3}{7}+\dfrac{17}{12}\right):\dfrac{4}{5}\)

\(=\left[\left(\dfrac{10}{7}-\dfrac{3}{7}\right)+\left(\dfrac{17}{12}-\dfrac{5}{12}\right)\right].\dfrac{5}{4}\)

\(=\left(1+1\right).\dfrac{5}{4}\)

\(=2.\dfrac{5}{4}\)

\(=\dfrac{5}{2}\)