When you roll a six-sided number cube you can get the next set of possible results:
[tex]\lbrace1,2,3,4,5,6\rbrace[/tex]You have a total of 6 possible results.
From the set of possible results you get the set of presults that are 1 or 6:
[tex]\lbrace1,6\rbrace[/tex]You have 2 results that are 1 or 6
The probability of rolling (1 or 6) is: The number of results that are 1 or 6 divided in the total number of possible results:
[tex]P(1or6)=\frac{2}{6}=\frac{1}{3}[/tex]Then, the probability of rolling (1 or 6) is 1/3