This article is from the Magic: The Gathering Rules FAQ, by Patrik Linell (pls@claymore.nu) with numerous contributions by others.
Yes. When calculating what you have to pay to cover the cost of a
spell, you first take the mana cost (printed on the card), then add
increasers (kicker costs, Gloom) and then apply reducers (Familiars,
Medallions).
 
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