Giải thích các bước giải:
A, 4/3 -(1/2-1) :3/4
= 4/3 - (-1/2) : 3/4
= 4/3 - (-2/3)
= 4/3 + 2/3
= 2
C, ( 4/19+ 5/78- 31/62 ) - ( 5/78 - (-31/62) -87/91 )
= 4/19 + 5/78 - 31/62 - 5/78 -31/62 + 87/91
= 4/19 + (5/78 - 5/78) - (31/62 + 31/62) + 87/91
= 4/19 + 87/91
= 2017/1729
D , | -7/3 | -2/3 : ( 25% - 0,3 )
= 7/3 - 2/3 : (1/4 - 3/10)
= 7/3 - 2/3 : (-1/20)
= 7/3 - (-40/3)
= 47/3