a: \(\dfrac{5}{12}+\dfrac{-11}{15}-\dfrac{49}{60}\)
\(=\dfrac{25}{60}-\dfrac{44}{60}-\dfrac{49}{60}=\dfrac{-68}{60}=-\dfrac{17}{15}\)
b: \(\dfrac{8}{15}+\dfrac{-7}{18}-\dfrac{13}{90}\)
\(=\dfrac{48}{90}-\dfrac{35}{90}-\dfrac{13}{90}\)
=0
c: \(-3\dfrac{3}{4}+\dfrac{-10}{25}+\dfrac{-7}{20}\)
\(=-\dfrac{15}{4}+\dfrac{-2}{5}+\dfrac{-7}{20}\)
\(=\dfrac{-75}{20}+\dfrac{-8}{20}+\dfrac{-7}{20}=\dfrac{-90}{20}=-\dfrac{9}{2}\)
d: \(\dfrac{11}{25}-\dfrac{5}{13}-\dfrac{-7}{17}-\dfrac{8}{13}+\dfrac{10}{17}\)
\(=\dfrac{11}{25}+\left(-\dfrac{5}{13}-\dfrac{8}{13}\right)+\left(\dfrac{7}{17}+\dfrac{10}{17}\right)\)
\(=\dfrac{11}{25}-1+1=\dfrac{11}{25}\)
e: \(\dfrac{1}{2}+\left(\dfrac{16}{21}+\dfrac{27}{13}\right)-\left(\dfrac{14}{13}-\dfrac{5}{21}\right)\)
\(=\dfrac{1}{2}+\dfrac{16}{21}+\dfrac{27}{13}-\dfrac{14}{13}+\dfrac{5}{21}\)
\(=\dfrac{1}{2}+1+1=\dfrac{5}{2}\)
`a, 5/12 + (-11)/15 - 49/60`
`= 25/60 - 44/60 - 49/60`
`= -68/60`
`= -17/15`
`b, 8/15 + (-7)/18 - 13/90`
`= 8/15 - 7/18 - 13/90`
`= 48/90 - 35/90- 13/90`
`= 0/90`
`= 0`
`c, -3 3/4 + (-10)/25 + (-7)/20`
`= -15/4 - 2/5 - 7/20`
`= -75/20 - 8/20 - 7/20`
`= -90/20`
`= -9/2`
