Đáp án:
`a, 3/8 . 19 1/3 - 3/8 . 33 1/3`
`= 3/8 (19 1/3 - 33 1/3)`
`= 3/8 [(19 - 33) + (1/3 - 1/3)]`
`= 3/8 . (-14)`
`= -21/4`
`b, 12,5 .(-5/7) + 1,5 .(-5/7)`
`= (-5/7) .(12,5 + 1,5)`
`= (-5/7) . 14`
`= -10`
`c, 3/5 : (-1 1/15 - 1/6) + 3/5 : (- 1/3 - 1 1/15)`
`= 3/5 : (-16/15 - 1/6) + 3/5 : (-1/3 - 16/15)`
`= 3/5 : (-32/30 - 5/30) + 3/5 : (-5/15 - 16/15)`
`= 3/5 : (-37)/30 + 3/5 : (-7)/5`
`= 3/5 . (-30)/37 + 3/5 . (-5)/7`
`= 3/5 .(-30/37 - 5/7) = 3/5 .(-210/259 - 185/259)`
`= 3/5 . (-395)/259`
`= -237/259`
`d, (-3/4 + 2/5) : 3/7 + (3/5 + (-1)/4) : 3/7`
`= (-3/4 + 2/5) . 7/3 + (3/5 - 1/4) . 7/3`
`=7/3 . (-3/4 + 2/5 + 3/5 - 1/4)`
`= 7/3 . [(-3/4 - 1/4) + (2/5 + 3/5)]`
`= 7/3 . (-1 + 1) = 7/3 . 0`
`=0`