I have a Sharp EL-531VH (the transparent blue) calculator, and every so often, i will press 'equals' and my calculation will be subtracted by or multiplied by a symbol K (looks like |K)...its not as though i accidentally press any buttons either, its seems to happen a lot, its goddamn annoying, i reset the calculator, and it still happens, randomly popping into my equations (mostly when i enter single line fractions so it can simplify them), does this happen for anybody else? can anybody tell me what it is or how to stop it from happening?? i try other peoples calculators and it does it too and i think it will reealy get on my nerves in the exam