Casio fx 991es Plus Scientific Calculator, (2nd Edition)

Casio fx-991ES Plus Scientific Calculator (2nd Edition)

Casio fx-991ES Plus Scientific Calculator (2nd Edition) is one of Casio’s most trusted and best-selling advanced scientific calculators, specially designed for SSC, HSC, Admission, Engineering, Diploma, and university-level mathematics and science students. This model belongs to the upgraded ES PLUS 2nd Edition series and offers a very balanced combination of Natural Textbook Display, 417 built-in functions, dual power system, advanced equation solving, matrix/vector operations, and calculus support in an easy-to-use body design. Casio officially identifies it as a non-programmable, non-graphing scientific calculator with 10+2 digit display, solar+battery backup, and premium academic calculation tools.

This calculator is especially popular among students because it offers high-level scientific features without becoming complicated like programmable models. Users can perform:

• Differential calculation
• Integral calculation
• Simultaneous equation solving
• Polynomial equation solving
• Matrix calculation
• Vector calculation
• Complex number operations
• CALC and SOLVE functions
• Table generation
• Base-N calculation
• Scientific constants
• Metric conversions
• Statistical regression analysis

all from one compact device. Casio confirms that the calculator contains 417 scientific functions in total.

General Information

• Brand: Casio
• Model: fx-991ES Plus
• Edition: 2nd Edition
• Series: ES PLUS
• Calculator Type: Advanced Scientific Calculator
• Programmable: No
• Graphing: No
• Suitable For: SSC, HSC, Admission, Engineering, University, Polytechnic

Display Specifications

• Display Type: Natural Textbook Display
• LCD Type: Dot Matrix Display
• Digit Capacity: 10 + 2 Digits
• Equation View: Book style mathematical display
• Fraction/Root Display: Yes
• Easy Cursor Navigation: Yes

Power System

• Power Supply: Dual Power (Solar + Battery)
• Battery Life: Approx. 3 Years
• Auto Power Off: Yes

Design & Physical Body

• Dimensions: 161.5 × 77 × 11.1 mm
• Weight: Approx. 95 g
• Keys: Durable Plastic Keys
• Fast Typing: 2-Key Rollover
• Body Design: Slim Rounded Body
• Hard Cover: Slide-on Hard Case Included

Memory Features

• Variables: 9
• Answer Memory: Yes
• Independent Memory: Yes
• Memory Protection: Yes
• Reset Function: Yes

Total Functions

• Built-in Functions: 417 Functions

Basic Calculation Functions

• Basic Arithmetic
• Fraction Calculation
• Percentage
• Reciprocal
• Factorial
• π and e
• Square / Cube / Root
• Degree Minute Second
• Bracket Calculation
• Rounding Function

Advanced Scientific Functions

• Trigonometric Functions
• Inverse Trigonometric
• Hyperbolic Functions
• Logarithm / Natural Log
• Exponential Calculation
• Summation
• Combination / Permutation
• Coordinate Conversion
• Random Number / Random Integer

Higher Mathematics & Engineering Functions

• Differential Calculation
• Integral Calculation
• Equation Solver
• Polynomial Solver
• Matrix Calculation
• Vector Calculation
• Complex Number Calculation
• Base-N Calculation
• CALC Function
• SOLVE Function
• Multi Replay

Statistics & Data Analysis

• 1 Variable Statistics
• 2 Variable Statistics
• Standard Deviation
• Regression Analysis
• STAT Data Editor
• Table Function

Science Utility Functions

• Scientific Constants
• Metric Conversion
• Logical Operators