Question:
If one was spacing out during shofar (thinking of other matters), does he still fulfill the mitzvah?
Answer:
The halacha is that mitzvos mentioned in the Torah need intention (kavanah) and without it one does not fulfill the mitzvah. The custom is to blow 100 blasts, so if you had already heard enough of the shofar as far as required by the Torah, lack of intention is not a problem.
Sources:
O:CH 60:4 & Mishnah Berurah 10 Biur Halachah ד”ה י”א
