The possible outcomes for a die throw are 1, 2, 3, 4, 5, 6. The outcomes where the number is 5 or less are:
\[
1, 2, 3, 4, 5.
\]
Thus, there are 5 favorable outcomes. The total number of possible outcomes is 6. Therefore, the probability is:
\[
\frac{5}{6}.
\]
Thus, the correct answer is \( \boxed{\frac{5}{6}} \).