I need one graphic calculator for my mathematics class. I already have one but I haven’t used it for about five years now. I am not even sure whether it would work or not. I bought few cheap aaa batteries to check whether it works or not. I found that the calculator was no good. Now I am bit perplexed. Is it because of the calculator or cheap batteries. Would any expensive battery would work for me. I want to ask if there is any difference between cheap batteries and expensive ones? Please get back to me as soon as possible. Thanks.