During an Uno game, can one player put multiple cards of the same number but not the same color on top of each other, with the first card the same as the previous one in the Discard Stack?
You may only play a single card each turn and note the rules mention playing "a card" not multiple.
You have to match either by the number, color, or the symbol/Action. For instance, if the Discard Pile has a red card that is an 8 you have to place either a red card or a card with an 8 on it. You can also play a Wild card (which can alter current color in play).