H24
H9
27 tháng 7 lúc 14:41

\(a.3\dfrac{5}{11}+\dfrac{5}{19}+1,75-\dfrac{5}{11}+\dfrac{14}{19}\\ =3+\dfrac{5}{11}+\left(\dfrac{5}{19}+\dfrac{14}{19}\right)-\dfrac{5}{11}+\dfrac{7}{4}\\ =3+\left(\dfrac{5}{11}-\dfrac{5}{11}\right)+1+\dfrac{7}{4}\\ =4+\dfrac{7}{4}\\ =\dfrac{23}{4}\\ b.\dfrac{1}{5}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\\ =\dfrac{1}{5}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}\\ =\dfrac{1}{5}+\dfrac{4}{5}\\ =1\\ c.\dfrac{4}{5}\cdot15\dfrac{2}{3}-\dfrac{4}{5}\cdot20\dfrac{2}{3}\\ =\dfrac{4}{5}\cdot\left(15+\dfrac{2}{3}-20-\dfrac{2}{3}\right)\\ =\dfrac{4}{5}\cdot\left(-5\right)\\ =-4\)

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NT

a: \(3\dfrac{5}{11}+\dfrac{5}{19}+1,75-\dfrac{5}{11}+\dfrac{14}{19}\)

\(=\left(3+\dfrac{5}{11}-\dfrac{5}{11}\right)+\left(\dfrac{5}{19}+\dfrac{14}{19}\right)+1,75\)

=3+1+1,75

=5,75

b: \(\dfrac{1}{5}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\)

\(=\dfrac{1}{5}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}\)

\(=\dfrac{1}{5}+\dfrac{4}{5}=\dfrac{5}{5}=1\)

c: \(\dfrac{4}{5}\cdot15\dfrac{2}{3}-\dfrac{4}{5}\cdot20\dfrac{2}{3}\)

\(=\dfrac{4}{5}\left(15+\dfrac{2}{3}-20-\dfrac{2}{3}\right)\)

\(=\dfrac{4}{5}\cdot\left(-5\right)=-4\)

d: \(75\%-3\dfrac{3}{4}+\dfrac{12}{5}:0,2\)

\(=\dfrac{3}{4}-3-\dfrac{3}{4}+\dfrac{12}{5}:\dfrac{1}{5}\)

\(=-3+\dfrac{12}{5}\cdot5=-3+12=9\)

e: \(2^3+3\cdot\left(\dfrac{1}{9}\right)^0-\dfrac{1}{2^2}\cdot4\)

\(=8+3-\dfrac{4}{4}\)

=11-1=10

f: \(\dfrac{4}{9}\cdot\left(-\dfrac{2}{13}\right)+\left(-\dfrac{5}{18}\right)\cdot\dfrac{2}{13}\)

\(=-\dfrac{2}{13}\left(\dfrac{4}{9}+\dfrac{5}{18}\right)\)

\(=-\dfrac{2}{13}\left(\dfrac{8}{18}+\dfrac{5}{18}\right)=-\dfrac{2}{13}\cdot\dfrac{13}{18}=-\dfrac{2}{18}=-\dfrac{1}{9}\)

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