Question

[Thư Minh]

Answer 1

[⭐Hannie⭐]

\(a,\left(7+3\dfrac{1}{4}-\dfrac{3}{5}\right)+\left(0,4-5\right)-\left(4\dfrac{1}{4}-1\right)\\ =7+\dfrac{13}{4}-\dfrac{3}{5}+\dfrac{4}{10}-5-\dfrac{17}{4}+1\\ =\left(7-5+1\right)+\left(\dfrac{13}{4}-\dfrac{17}{4}\right)+\left(-\dfrac{3}{5}+\dfrac{4}{10}\right)\\ =3+\left(-\dfrac{4}{4}\right)+\left(-\dfrac{5}{5}\right)\\ =3+\left(-1\right)+\left(-1\right)\\ =2+\left(-1\right)\\ =1\)

\(b,\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)-\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]\\ =\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)-\left(\dfrac{4}{8}+\dfrac{3}{8}\right)\right]\\ =\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)-\dfrac{7}{8}\right]\\ =\dfrac{2}{3}-\left[\left(-\dfrac{14}{8}\right)-\dfrac{7}{8}\right]\\ =\dfrac{2}{3}-\left(-\dfrac{21}{8}\right)\\ =\dfrac{2}{3}+\dfrac{21}{8}\\ =\dfrac{79}{24}\)

\(c,\left(9-\dfrac{1}{2}-\dfrac{3}{4}\right):\left(7-\dfrac{1}{4}-\dfrac{5}{8}\right)\\ =\left(\dfrac{36}{4}-\dfrac{2}{4}-\dfrac{3}{4}\right):\left(\dfrac{56}{8}-\dfrac{2}{8}-\dfrac{5}{8}\right)\\ =\dfrac{31}{4}:\dfrac{49}{8}\\ =\dfrac{31}{4}\times\dfrac{8}{49}\\ =\dfrac{62}{49}\)

\(d,3-\dfrac{1-\dfrac{1}{7}}{1+\dfrac{1}{7}}\\ =3-\dfrac{\dfrac{7}{7}-\dfrac{1}{7}}{\dfrac{7}{7}+\dfrac{1}{7}}\\ =3-\dfrac{\dfrac{6}{7}}{\dfrac{8}{7}}\\ =3-\dfrac{6}{7}\times\dfrac{7}{8}\\ =3-\dfrac{42}{56}\\ =3-\dfrac{21}{28}\\ =\dfrac{9}{4}\)

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