What's an easy way to fix a damaged floor tile?
Glop some epoxy on it. For a less blatant but still visible repair, mix some marble dust (given the tile color) into the epoxy, or choose a white rather than clear epoxy and mix (but do not mix too well, for this pattern) some pigment into it (after throughly mixing the epoxy, first.)

Age can somewhat be inferred by how clean or dirty it is, as a chip will tend to collect dirt and be harder to clean than the surface of the floor.

The proper fix is to reach for your stash of spare tiles (problem if there isn't such a stash) and break out the remainder of this tile, then replace it. But you wanted easy...