tính giá trị biểu thức a) 4+ 11/8 -5/6 b) (1/2 + 4/7 ) - (3/7 - 3/10) Giúp mình nha

$\text{a)}$ `4 + \frac{11}{8} - \frac{5}{6}`

`= 4 + \frac{66}{48} - \frac{40}{48}`

`= 4 + \frac{66 - 40}{48}`

`= 4 + \frac{26}{48}`

`= 4 + \frac{26 : 2}{48 : 2}`

`= 4 + \frac{13}{24}`

`= \frac{96}{24} + \frac{13}{24}`

`= \frac{109}{24}`

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$\text{b)}$ `(\frac{1}{2} + \frac{4}{7}) - (\frac{3}{7} - \frac{3}{10})`

`= \frac{1}{2} + \frac{4}{7} - \frac{3}{7} + \frac{3}{10}`

`= \frac{1}{2} + \frac{1}{7} + \frac{3}{10}`

`= \frac{35}{2 × 35} + \frac{10}{7 × 10} + \frac{3 × 7}{10 × 7}`

`= \frac{35}{70} + \frac{10}{70} + \frac{21}{70}`

`= \frac{35 + 10 + 21}{70}`

`= \frac{66}{70}`

`= \frac{66 : 2}{70 : 2}`

`= \frac{33}{35}`