Ancient Totals Calculation

My character has the Litany of the Undaunted ring set which gives 750% damage for each Ancient item And she is wearing the Legacy of Dreams jewel which currently gives me 108.75% damage for Legendary items and double that for Ancient items.
Do these numbers stack, multiply, or is one of them rendered useless? Can you tell me how much damage I get from my Ancient items, and explain how you figured that out?
Thank you.

The gem and ring set do not stack.

Each ancient item is additive to each other.

In total, with 13 ancient items equipped, you will get 750 x 13 = 9750.

So it ends up being a 9750% multiplier at max capacity.

Read the description of the LoD gem. It states that you cannot have any set bonus active.

Thank you, both of you. You are correct. Since the Litany of the Undaunted provides a set bonus, the Legacy of Dreams jewel is ineffective with that ring set.
Thank you again.