a) The die is a cube with six faces and equal probability for each face. The number 5 appears on one face. Thus, the probability is:
\frac{1 \text{ favorable outcome}}{6 \text{ total outcomes}} = \frac{1}{6}
b) All numbers on a standard die (1 to 6) are less than 7, so all outcomes are favorable:
\frac{6 \text{ favorable outcomes}}{6 \text{ total outcomes}} = 1
c) The numbers 1 and 4 appear, each on one face of the die:
\frac{2 \text{ favorable outcomes (1 or 4)}}{6 \text{ total outcomes}} = \frac{1}{3}
Answer for a): $\frac{1}{6}$
Answer for b): $1$
Answer for c): $\frac{1}{3}$