Đáp án + Giải thích các bước giải:
`a`, $\dfrac{2}{3}$ `- (` $\dfrac{5}{4}$ `-` $\dfrac{3}{2}$ `)` `+` `(` $\dfrac{1}{4}$ `-` $\dfrac{5}{2}$ `+` $\dfrac{1}{3}$ `)`
`=` `(` $\dfrac{2}{3}$ `+` $\dfrac{1}{3}$ `)` `-` `(` $\dfrac{5}{4}$ `-` $\dfrac{1}{4}$ `)` `-` `(` $\dfrac{5}{2}$ `-` $\dfrac{3}{2}$ `)`
`= 1 - 1 - 1`
`= -1`
`b`, $\dfrac{1}{2}$ `-`` ( `$\dfrac{5}{3}$ `-` $\dfrac{3}{4}$ `+` $\dfrac{7}{6}$` )` `+` $\dfrac{5}{4}$ `-` $\dfrac{7}{2}$
`=` $\dfrac{1}{2}$ `-` $\dfrac{5}{3}$ `+` $\dfrac{3}{4}$ `-` $\dfrac{7}{6}$ `+` $\dfrac{5}{4}$ `-` $\dfrac{7}{2}$
`=``( `$\dfrac{1}{2}$ `-` $\dfrac{7}{2}$ `)` `+` `(` $\dfrac{3}{4}$ `+` $\dfrac{5}{4}$ `) ``-` `(` $\dfrac{5}{3}$ `+` $\dfrac{7}{6}$ `)`
`= -3 + 2 -` $\dfrac{17}{6}$
`=` $\dfrac{-23}{6}$
