Resistances + reduced/converted elemental damage.

Curious how this calculation works.

Say you have 80% resists and -5% cold damage taken (or converted) does it work similarly to how attacks vs armour + endurance charges/physical reduction?

I.E.

is 80% of damage taken from total due to resists then 5% of original total also taken from resists (as happens with armour + phys reduction)

Or

is 5% only taken from the remaining damage resulting in a 1% total reduction instead of 5%?

Same question for converted damage:

If you have 80% cold resist, and 20% of cold damage taken as lightning, do you end up taking 0% cold and 20% lightning, or 16% cold and 4% lightning, or 16% cold and 20% lightning (just assume 0% lightning resist).

Resistances come first, less damage taken is next.
Conversion happens before all damage.

Resistances and Less Damage Taken are separate modifiers and as such apply separately.

If you take 100 cold damage, have 80% cold resistance and 5% less cold damage taken you will now take:
100 * (1-0,8) * (1-0,05) = 20 * 0,95 = 19 cold damage.

If you take 100 physical damage, have 50% physical damage reduction, 30% of physical damage taken as cold, 80% cold resistance and 5% less cold damage taken you will now take:

(100 * 0,7) * (1-0,5) = 35 physical damage
(100 * 0,3) * (1-0,8) * (1-0,05) = 5,7 cold damage

Thanks, that clears everything up for me