Price presentation on product page with or without sales tax

Hi,

Can someone help clarify this query.

If my setting for national sales taxes at 20% is programmed with the "on mode", does this mean that I have to present my prices without the extra 20% sales tax ?

Example if product price at 120€ (with tax at 20% included), on my product sheet, I will have to indicate the price at 100€ (exclusive of the 20% sales tax). At checkout, this 20% will be added to the total amount.