Đáp án + Giải thích các bước giải:
`a)` `7/9 + (-1) / 3 + 5/27`
`= 21/27 + (-9) / 27 + 5/27`
`= 12/27 + 5/27`
`= 17/27`
`b)` `1/3 - 19/28. 56/57`
`= 1/3 + (-2) / 3`
`= (-1) / 3`
`c)` `5/3. 3 ^ 2/2. 4/5 - 1`
`= 5/3. 9/2. 4/5 - 1`
`= 15/2. 4/5 - 1`
`= 6 - 1`
`= 5`
`d)` `1/2 . (2/9 + 3/7 - 5/27)`
`= 1/2 . (42/189 + 81/189 + (-35)/189)`
`= 1/2 . 88/189`
`= 44/189`
`e)` `6/25 . (-15)/4 + (-7)/5`
`= (-9)/10 + (-7)/5`
`= (-9)/10 + (-14)/10`
`= (-23)/10`
`f)` `1/3 . 5/7 - 7/27 . 36/14`
`= 1/3 . 5/7 - 7/27 . 18/7`
`= 5/21 - 2/3`
`= 5/21 + (-14)/21`
`= (-9)/21 = (-3)/7`
`k)` `(1/2)^2 - 45/54 + 1/3`
`= 1/4 - 5/6 + 1/3`
`= 3/12 + (-10)/12 + 4/12`
`= (-7)/12 + 4/12`
`= (-3)/12 = (-1)/4`
`h)` `(3/8 + (-3)/4 + 7/12) : 5/6 + 1/2`
`= (9/24 + (-18)/24 + 14/24) : 5/6 + 1/2`
`= (-9/24 + 14/24) : 5/6 + 1/2`
`= 5/24 . 6/5 + 1/2`
`= 1/4 + 1/2`
`= 1/4 + 2/4`
`= 3/4`
`p)` `1/2 + 3/4 - (3/4 - 4/5)`
`= 1/2 + 3/4 - 3/4 + 4/5`
`= (1/2 + 4/5) + (3/4 - 3/4)`
`= (5/10 + 8/10) + (3/4 +` `(-3)/4)`
`= 13/10 + 0`
`= 13/10`
`q)` `(7/8 - 3/4). 1 1/3 -` `2/7.(3,5)^2`
`= (7/8 + (-6)/8) . 4/3 -` `2/7. (7/2)^2`
`= 1/5 . 4/3 - 2/7 . 14/4`
`= 4/15 - 1`
`= 4/15 + (-15)/15`
`= (-11)/15`
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