Formula: (alchemy + 3 x herb lore + 2 x animal lore + 5 x DX) / 10

Formula: (swim + survival + bind) / 3 + modifier

Formula: (orientation + survival + perception) / 3

Formula: (track + animal lore + survival) / 3

Formula: (2 x plant lore + survival) / 3

Formula: (3 x self-control + 4 x perception + hide + sneak + survival) / 10

Formula: (3 x self-control + 4 x perception + hide + sneak + streetwise) / 10