How do you know if a middle school boy likes you?

Ok so i like this boy in middle school and i sit in back of him in class. He always turns around and calls me by my nickname. He always stares at me when he turns around for more then 5 seconds without even blinking or anything. He always throws my papers and books on the floor and he makes me pick them up (but its okay because hes like flirting while he does it). My friends say that he always flirts with me. Also, my friend told him that i wanted to kiss him, and i don't think he said anything or i didn't get the full story yet. Like today i was in class and he took a picture of me and he drew on my picture. I got mad at him and he tried to fix it :). Then he took my planner and he wrote down his number and he wrote down my number, and he called me. He took apart the spiral thing that holds the planner together. He always steals my pens and takes out the springs and now i don't have any pens left lol! Basically, does he like me? Should i tell him? HELP! I don't really know what to do! Everyone thinks he likes me, but i'm not sure! Thanks so much [: