Đáp án:
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`A = (5/2 - 3/4 + 4/3) - (4/3 + 3/4 - 2) - (1/2 - 3/7)`
`↔ A = 5/2 - 3/4 + 4/3 - 4/3 - 3/4 + 2 - 1/2 + 3/7`
`↔ A = (5/2 - 1/2 + 2)+ (-3/4 - 3/4) + (4/3 - 4/3) + 3/7`
`↔ A = (2 + 2) - 3/2 + 3/7`
`↔ A = 4 - 3/2 + 3/7`
`↔ A = 8/2 - 3/2 + 3/7`
`↔ A = 5/2 + 3/7`
`↔ A = 35/14 + 6/14`
`↔ A = 41/14`
Vậy `A = 41/14`