How do i win in this situation?

ok my bro thinks he is smart because he watches History Channel all the time or the science channel and all those other educated channels! ill give him this much he knows a little bit of stuff about the past, but he doesnt know how to do 10th grade chemistry he's also a 9th grade dropout im in the 10th grade i plan on attending college but i need to know how to get him off my back! its anoying he thinks he is so smart! and i mean he is always saying and i qoute "im smart your stupid" its anoying help me please!