What are the official Uno rules?

Question

Accepted Answer

Skip:
The next player is "skipped".
Reverse:
Reverses the direction of play.
Draw 2:
The next player must draw 2 cards and lose a turn.
Draw 4:
Changes the current color plus the next player must draw 4 cards and lose a turn.
Wild Card:
Play this card to change the color to be matched.
Challenge Draw 4:
If you think the player who played a Draw 4 on you has a card of the matching color, you can challenge this player. If you are right, this player must draw 4 cards instead of you. Otherwise, you'll draw 4 cards PLUS 2 extra cards!
Challenge UNO:
Challenge your opponent for not calling UNO. If they are caught, your opponent must draw two cards!
Stack:
+2 and +4 cards can be stacked. +2 can only be stacked on +2. Can only play a +2 on a +2 if holding a +2 and +4. A player that can't add to the stack must draw the total.
7-0:
When someone plays a 7, that player must swap hands with another player. When anyone plays a 0, everyone rotates hands in the direction of play.
Force Play:
If you draw a playable card, it will be played automatically.

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