9. The rational number that is equal to its negative is zero (0)
10. [tex]\sf \dfrac{1}{3} ( 6 \ * \ \dfrac{4}{3} )[/tex] can be written as [tex]\sf ( \dfrac{1}{3} *6)*\dfrac{4}{3}[/tex] using associate property.
associative property is when numbers are changed within the parenthesis with out the change in result.
formula of associative property : a(bc) = (ab)c
