4)
( 3/2 -4/3)^2 : (1/2)^3 = (9/6 - 8/6)^2 : 1/8 = (1/6)^2 x 8/1 = 1/36 x 8 = 8/36 = 2/9
6)
a= 16/3 x [(75/90 -1) : 6/9 ]^3
a= 16/3 x [(15/18 -1) x 3/2] ^3
a= 16/3 x (-3/18 x 3/2) ^3
a= 16/3 x (-1/6x3/2)^3
a= 16/3 x (-1/4)^3
a= 16/3 x (-1/16x4)
a= -1/12
|a|= 1/12
