Notation

$\Pr(V=v)$: the probability that (random) variable V takes on value v.

$$\Pr(S \ge 8) = 0.9.$$

$\Pr(s)$: the probability that the given propositional sentence s is true.

$$\Pr(\mbox{\rm happy}) = 0.40.$$

$\Pr(\mbox{\rm happy}\cdot \overline{\mbox{\rm hungry}}) = 0.39$ (can't be larger, even though it's not very likely for me to be happy when I'm hungry).