Tính

C= ( 12/35 - 6/7 + 18/14 ) : 6/-7 -  -2/5 - 1

D= [ -54/64 - ( 1/9 : 8/27) : -1/3] : -81/128

E= [ 193/-17 ( 2/193 - 3/386) + 11/34] : [( 7/1931 + 11/3862) 1931/25 + 9/2]

G =(-5/7 - 7/9 + 9/11 - 11/13 )(3 - 3/4)

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       (10/21 + 14/27 - 6/11 + 22/39 ) : ( 2 - 2/3