Anoregon
The flight plan I just filed with the agency list me, my men, Dr. Pavel here. But only one of you!
The question mark is there if you haven't completed the bestiary entry (which is automatic as you kill more of that creature) and indicates you don't know the exact value. The upper number (defenses) is basically the number your attack roll has to beat to hit them (after bonuses and whatnot, it's all behind the scenes stuff.) The lower numbers are actual damage reductions, and the numbers listed there are subtracted from attacks of that type.
So for example, if you see a 10 next to the damage reduction symbol that looks like a sword, a slashing attack that does 30 base damage would do 20 after damage reduction.
So for example, if you see a 10 next to the damage reduction symbol that looks like a sword, a slashing attack that does 30 base damage would do 20 after damage reduction.