Casio fx-991ES PLUS 2nd Edition Scientific Calculator – Blue, 417 Functions

The Casio fx-991ES PLUS 2nd Edition is a non-programmable, non-graphing scientific calculator with 417 functions. Natural Textbook Display shows fractions, roots, powers, and other expressions in textbook layout on a dot-matrix screen with a 10-digit mantissa and a 2-digit exponent. Display format can be Fix, Sci, or Norm, and engineering notation is available.

Equation mode solves simultaneous linear equations with two or three unknowns, quadratic equations, and cubic equations. CALC substitutes values into an expression, and SOLVE searches for a numeric solution. Integration, differentiation, summation, and a function table are included. Matrix, vector, and complex-number calculations are available, as is base-n work in binary, octal, and hexadecimal, including logical operations.

Statistics use a list-based editor for mean, sum, standard deviation, and regression. Memory provides nine variables (A, B, C, D, E, F, X, Y, and M), independent memory, and answer memory. The current Casio manual for this model lists 40 scientific constants from CODATA 2014 and 40 metric conversion commands. Standard scientific functions include trigonometry, hyperbolics, exponents, logarithms, permutations, combinations, factorials, and coordinate conversion.

The body measures 161.5 x 77 x 11.1 mm (D x W x H) and weighs 95 g including the battery. Keys are plastic. A solar cell runs the calculator in sufficient light, and one LR44 (GPA76) button battery covers low light. Casio rates battery life at about three years at one hour of use per day, with auto power off. Operating temperature is 0°C to 40°C. A slide-on hard case is included. This listing is the blue model, product code FX-991ESPLUS-2BU.

• 417 functions
• Natural Textbook Display on a dot-matrix screen
• 10-digit mantissa and 2-digit exponent
• Non-programmable and non-graphing
• Equation mode for 2- and 3-unknown linear systems, quadratics, and cubics
• CALC and SOLVE
• Integration, differentiation, summation, and numeric tables
• Matrix, vector, and complex-number calculations
• Binary, octal, and hexadecimal calculations with logical operations
• List-based statistics, including regression
• 9 variables plus independent memory and answer memory
• 40 scientific constants and 40 metric conversions
• Solar power with one LR44 battery and auto power off
• Slide-on hard case

• Casio fx-991ES PLUS 2nd Edition calculator (blue)
• Slide-on hard case
• One LR44 (GPA76) button battery supplied with the calculator