Bài `2:`
`a) -1,6 : (1+2/3)`
` = -1,6 : 5/3`
` = -24/25`
`b) (-2/3)+3/4 - (-1/6) + (-2/5)`
` = -2/3 + 3/4 + 1/6 - 2/5`
` = 1/12 + 1/6 - 2/5`
` = 1/4 - 2/5`
` = -3/20`
`c) ((-3)/7 : 2/11 + (-4)/7 : 2/11) . 7/33`
` = ((-3)/7 . 11/2 + (-4)/7 . 11/2) . 7/33`
` = ((-3)/7 + (-4)/7) . 11/2 . 7/33`
` = -1 . 11/2 . 7/33`
` = (-11)/2 . 7/33`
` = (-7)/6`
`d) (-5)/8 + 4/9 : (-2)/3 -7/20 . (-5)/14`
` = (-5)/8 -2/3 + 1/8`
` = -31/24 + 1/8`
` = -7/6`
Bài `3:`
`a) (-2)/3 + 7/2 . 3/4`
` = (-2)/3 + 21/8`
` = 47/24`
`b) (-4)/9 : 16/27 + (-1)/4`
` = (-4)/9 . 27/16 -1/4`
` = (-3)/4 - 1/4`
` = -1`
`c) 4/11 . (-2)/9 + 4/11 . (-8)/9 + 4/11. 1/9`
` = 4/11 . ((-2)/9 + (-8)/9 + 1/9)`
` = 4/11 . (-1)`
` = -4/11`
`d) [-12 5/9 .(5/7 + 4 1/5)] : 5/6`
` = [(-113)/9 . (5/7 + 21/5)] . 6/5`
` = ((-113)/9 . 172/35) .6/5`
` = (-19436)/315 . 6/5`
` = (-38872)/525`
