A:AnswerThis solar powered with battery back up battery is a standard LR44 ( AN ALKALINE BUTTON CELL BATTERY). The LR44 is a very common battery and is produced by many large brands such as Toshiba, Maxell, Energizer, and more.
A:AnswerThe only electric calculator would be a Casio printing calculator. Best Buy carries the HR-170RC.
Any Casio desk or basic calculator are 2-way power, solar with battery back up.
A:AnswerI can't get it to do that either using the % symbol under rate set. The only way I could do it, was use .05 as the 5% and divide 100 by that and then subtract that from the 100. Sorry I couldn't give you better information. I just bought mine to do the simple math of add/subtract and multiply/divide. Maybe someone else can help you.