A standard number cube is a fair-die.
The sample space for a die is six (6).
[tex]S=\mleft\lbrace1,2,3,4,5,6\mright\rbrace[/tex]The probability of an event, E , is defined mathematically as:
[tex]Pr(E)=\frac{\text{number of favourable outcome}}{\text{number of sample space}}[/tex]To obtain the probability of getting a 6 or an even number, we have:
[tex]\begin{gathered} Pr(6\text{ or even)=}\frac{1}{6}+\frac{3}{6} \\ Pr(6\text{ or even)=}\frac{4}{6} \\ Pr(6\text{ or even)=}\frac{2}{3} \end{gathered}[/tex]Hence, the correct option is option C