[ If ever your not sure on what to roll just roll an unmodified D20<img alt=":)" src="./images/smilies/smile.gif" title="Smile"/>we can add the modifiers later. But if it says +3 that is likely your to hit modifier so it would be 1d20+3 vs the creatures AC, which should be less as he is in a grapple, if he had any dex bonus.]