Question

39/40 - 7/9 : 2/3 x 2/7 = ?

20/63 : 8/9 + 5/6 x 51/70 = ?

 

Answer 1

77/120

27/28

Answer 2

\(\frac{39}{40}-\frac{7}{9}\div\frac{2}{3}\left(\times\frac{3}{2}\right)\times\frac{2}{7}\)\(=\frac{39}{40}-\frac{7\times3\times2}{3\times3\times2\times7}=\frac{39}{40}-\frac{1}{3}\)\(=\frac{117}{120}-\frac{40}{120}=\frac{77}{120}\)

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\(\frac{20}{63}\div\frac{8}{9}\left(\times\frac{9}{8}\right)+\frac{5}{6}\times\frac{51}{70}=\frac{5\times4\times9}{9\times7\times4\times2}+\frac{5\times17\times3}{3\times2\times5\times14}\)\(=\frac{5}{14}+\frac{17}{28}=\frac{10+17}{28}=\frac{28}{28}=1\)

Answer 3

9/40 - 7/9 : 2/3 x 2/7 = 77/120

20/63 : 8/9 + 5/6 x 51/70 = 27/28

mt cho nhanh bn oy !!!