Question

Tính hợp lý (nếu có thể)

a)\(\left(\dfrac{-19}{17}+\dfrac{3^2}{19}-1\dfrac{2}{3}\right)-\left(\dfrac{15}{17}-\dfrac{10}{19}\right)\)

b)\(40\%.\dfrac{-18}{25}-\dfrac{7}{25}:2,5-2023^0\)

c)\(\left(7,493-\dfrac{7}{11}\right)-\left(1\dfrac{4}{11}-2,507-50\%\right)\)

 

Answer 1

a: \(\left(-\dfrac{19}{17}+\dfrac{3^2}{19}-1\dfrac{2}{3}\right)-\left(\dfrac{15}{17}-\dfrac{10}{19}\right)\)

\(=-\dfrac{19}{17}+\dfrac{9}{19}-\dfrac{5}{3}-\dfrac{15}{17}+\dfrac{10}{19}\)

\(=-\dfrac{34}{17}+\dfrac{19}{19}-\dfrac{5}{3}\)

\(=-2+1-\dfrac{5}{3}=-1-\dfrac{5}{3}=-\dfrac{8}{3}\)

b: \(40\%\cdot\dfrac{-18}{25}-\dfrac{7}{25}:2,5-2023^0\)

\(=\dfrac{2}{5}\cdot\dfrac{-18}{25}-\dfrac{7}{25}\cdot\dfrac{2}{5}-1\)

\(=\dfrac{2}{5}\left(-\dfrac{18}{25}-\dfrac{7}{25}\right)-1=-\dfrac{2}{5}-1=-\dfrac{7}{5}\)

c: \(\left(7,493-\dfrac{7}{11}\right)-\left(1\dfrac{4}{11}-2,507-50\%\right)\)

\(=7,493-\dfrac{7}{11}-1\dfrac{4}{11}+2,507+50\%\)

\(=10-\dfrac{7}{11}-1-\dfrac{4}{11}+0,5\)

\(=9,5-1=8,5\)