@mister kitten,
1. proposition. For all x, if x is greater than or equal to 9, then x is greater than 8.
2. proposition. For all x, if x is greater than 8, then x is greater than or equal to 9.
These are converses of each other. Both are conditionals also called implications.
Formalization
1. prop. (∀x)(x≥9→x>8)
2. prop. (∀x)(x>8→x≥9)
Truth value
1. prop. is true and necessarily so.
2. prop is false and necessarily so. A counter example would be 8.5.
Note that if you change (2) slightly, then it becomes true:
2'. (∀n)(n>8→n≥9) (n is the set of natural numbers.)
What more do you want to know?