Casio FX-991MS Scientific Calculator (Gray) Product Description Many different people may need to use calculators depending on the daily tasks they face. Students often need them for schoolwork. Adults find them handy to have around the house or in a purse or briefcase for many reasons, including paying bills and balancing the checkbook. Office workers, especially in the finance and accounting fields, need them to calculate different things on a daily basis. The casio desk calculator comes in handy for all your multiple purposes and it's various features makes it easy to use . Casio adds fun and convenience to daily life. The brand is known for setting new trends. 				    	 					 From the Manufacturer  Non Programmable calculators to perform various mathematical calculations. Standard Models401 Functions2-Line DisplayTwo-way power     Two-way power (Solar + Battery)Solar powered when light is sufficient, battery powered when light is insufficient.    Plastic keysDesigned and engineered for easy operation.    S-V.P.A.M. (Super Visually Perfect Algebraic Method)All the features of the existing V.P.A.M. series plus a new 2-line display and a useful Replay function. All this helps to make mathematics easier to use and easier to understand than ever before.    STAT-data editorBack-step viewing and editing of input data.      Multi-replayQuick and easy recall of previously executed formulas for editing and re-execution.    10 + 2 digits10-digit mantissa + 2-digit exponential display.    Dot matrix displayHigh-resolution screen provides beautiful looking graphs every time.     FeaturesFraction calculationsCombination and permutationStatistics (STAT-data editor, Standard deviation, Regression analysis)9 variable memoriesComes with slide-on hard case