Question

[Thầy Tùng Dương]

(1,5 điểm) Tính

a) $0,2+1\dfrac{3}{7}-\dfrac{6}{5}$;

b) $\left( \dfrac{4}{5}-1 \right) \, : \, \dfrac{3}{5}-\dfrac{2}{3}. 0,5$.

Answer 1

[Dora]

\(a)0,2-1\dfrac{3}{7}-\dfrac{6}{5}\)

\(=\dfrac{1}{5}-\dfrac{10}{7}-\dfrac{6}{5}\)

\(=(\dfrac{1}{5}-\dfrac{6}{5}\)-\dfrac{10}{7}\)

\(=-1-\dfrac{10}{7}\)

\(=\dfrac{-17}{7}\)

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\(b)(\dfrac{4}{5}-1):\dfrac{3}{5}-\dfrac{2}{3}.0,5\)

\(=\dfrac{-1}{5}.\dfrac{5}{3}-\dfrac{2}{3}.\dfrac{1}{2}\)

\(=\dfrac{-1}{3}-\dfrac{1}{3}=\dfrac{-2}{3}\)