60đ, mỗi câu 10 điểm, hết sẩy

`a, 5 5/27 + 7/23 + 0,5. 5/27 + 16/23`

`= 140/27 + 7/23 + 5/54 + 16/23`

`= (140/27 + 5/54) + (7/23 + 16/23)`

`= 95/18 + 1`

`= 113/18`

`b, 35 1/6 : (-4)/5 - 45 1/6 : (-4)/5`

`= 35 1/6. (-5)/4 - 45 1/6. (-5)/4`

`= (-5)/4. (35 1/6 - 45 1/6)`

`= (-5)/4. [(35 - 45) + (1/6 - 1/6)]`

`= (-5)/4. [-10 + 0]`

`= (-5)/4. (-10)`

`= 25/2`

`c, 3/8. 27 1/5 - 51 1/5. 3/8 + 19`

`= 3/8. (27 1/5 - 51 1/5) + 19`

`= 3/8. [(27 - 51) + (1/5 - 1/5)] + 19`

`= 3/8. (-24) + 19`

`= -9 + 19`

`= 10`

`d, 25(-1/5)^3 + 1/5 - 2. (-1/2)^2 - 1/2`

`= 25. (-1)/125 + 1/5 - 2. 1/4 - 1/2`

`= (-1)/5 + 1/5 - 1/2 - 1/2`

`= 0 - (1/2 + 1/2)`

`= 0 - 1`

`= -1`

`e, (3,1 - 2,5) - (-2,5 + 3,1)`

`= 3,1 - 2,5 + 2,5 - 3,1`

`= (3,1 - 3,1) - (2,5 - 2,5)`

`= 0 - 0 `

`= 0`

`f, (-4/9 + 3/5) : 1 1/5 + (1/5 - 5/9) : 1 1/5`

`= 7/45 : 6/5 + (-16)/45 : 6/5`

`= 7/45. 5/6 - 16/45. 5/6`

`= 5/6. (7/45 - 16/45)`

`= 5/6. (-1)/5`

`= -1/6`