Can you help with math homework?

I have homework to do and I only have 2 problems left. The only thing is that we have been tought to only do it on a TI-83 calculator. My problem is that I dont own one of those. Is there one online? I couldnt do 2 of last nights problems for the same reason. I got a 75 on that homework check and my lowest grade so far besides that one is a 95. I need to get these last 2 done so I wont make another 75. Any ideas?