We bought them but how much dont use them.I use mine in science to look at labs but that is it. I use it in english bu the system worked last year without them. I don't get why we have them. I want them to work and I try to make them work but they dont. It is very annoying and strange that we are told to use them so much, but we don't. I think that the planing was poor and it is strange. I hate telling my parents that I need ot get something and taking their money and not using it. Sorry, but it makes me mad.