5/2 monster blocked by a 2/2 monster who wins in magic the gathering

[NIKTER]

if 5/2 monster is blocked by a 2/2 monster does 5/2 win or do both die?

[Kenji]

Both creatures will be destroyed, because combat damage is dealt by both creatures simultaneously. The 5/2 creature will deal 5 damage to the 2/2 creature, and the 2/2 creature will deal 2 damage to the 5/2 creature. Both creatures have received enough damage to be considered "lethal," and as such both will be destroyed and sent to the graveyard.

Now, either of the creatures having First Strike/Double Strike would change the answer. But, as you didn't mention either creature having First Strike or Double Strike, I'm assuming that you weren't asking about that.