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
