Resposta:

q)

[tex]-\dfrac{8}{3}\div(\dfrac{3}{6})=\\ \\\\ -\dfrac{8}{3}\times\dfrac{\not6^2}{\not3}=-\dfrac{16}{3}[/tex]

r)

[tex]\dfrac{3}{4}\times(-\dfrac{5}{2})=-\dfrac{15}{8}[/tex]

s)

[tex](\dfrac{8}{20})\times(-\dfrac{5}{2})=\dfrac{40}{40}=1[/tex]

t)

[tex]\dfrac{8}{5}\times(-\dfrac{5}{4})\times(-\dfrac{3}{2})=+\dfrac{120}{40}=+3[/tex]