Definitely.
Past papers are the key to maths exam success. I did every single one possible (AQA), including some from other exam boards!
I got an A* in the end for GCSE.
Don't stop there though! For A level, I did every single Core 1 paper for AQA. In the exam, I got an A - 95/100!
PAST PAPERS = SUCCESS
Edit : IF YOU ARE STUCK, ASK THE TEACHER. THEY ARE THERE FOR A REASON!