Question on order of operations (+% armor and Acrobatics)

There is a question I have for how the math is handled is this game, to help decide on my build.

I have +80% armor from various passives and I take Acrobatics. Do I just take -50% armor (leaving me with 130%), or is my entire armor total halved, dropping me to 90%?

The key word is "Less," armour and energy shield. This indicates that it is multiplicative with other stats. Therefore, your entire armor total is halved.

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Kabiras wrote:

The key word is "Less," armour and energy shield. This indicates that it is multiplicative with other stats. Therefore, your entire armor total is halved.

This.

Reduced = Additive
Less = Multiplicative

Same works the other way around with Increased and More.