magic the gathering sorceress queen 1 counter

[Warrior]

what if I use sorceress queen ability on a creature that has a +1/+1 counter?

[Arix]

Sorceress Queen's power/toughness setting ability applies in sublayer 7b, and the counter applies in 7d. So first the creature becomes 0/2, then the counter is applied and makes it 1/3.

[Warrior]

whats 7b and 7d?

[Arix]

Sublayers. When determining a creature's power and toughness, you move down the list of sublayers and apply them in order.

Say, for example, there are 8 cards in graveyards and you control a Lord of Extinction with two +1/+1 counters on it, and a Glorious Anthem. It gets hit by Sorceress Queen and About Face. Here's what you do:

Sublayer 7a: Characteristic-defining effects. The Lord's own ability makes it 8/8.
Sublayer 7b: Abilities that set power/toughness to a specific number. Queen makes it 0/2.
Sublayer 7c: Changes that modify but don't set p/t. Anthem makes it 1/3.
Sublayer 7d: Changes from counters. The two +1/+1 counters make it 3/5.
Sublayer 7e: Effects that switch power/toughness. About Face makes it a 5/3.

And there you go.