Casio Standard Scientific Calculator |FX-991ES Plus

🧮 General Information

• Type: Standard scientific calculator (non‑programmable, non‑graphing)
• Number of Functions: 417 built‑in functions (math, stats, etc.)
• Display: Natural Textbook Display (shows expressions like in textbooks)
• Display Digits: 10‑digit mantissa + 2‑digit exponent (10 + 2)
• Display Type: Dot‑matrix LCD

⚡ Power & Build

• Power Supply: Dual power — solar panel + battery (LR44)
• Battery Life: Approx. 3 years
• Auto Power Off: Yes
• Keys: Plastic keys with fast‑typing function (2‑key rollover)

• Memory:

  • 9 variables
  • Independent memory (M, M+, M‑)
  • Answer memory
  • Memory protection & reset
• Accessories Included: Hard case

📏 Physical Dimensions

• Size (Approx): 161.5 × 77 × 11.1 mm
• Weight: Approx. 95 g

🧠 Display & Format Options

• Numeric formats: Fix, Scientific, Normal
• Engineering notation
• Toggle calculation results format

📊 Calculation Capabilities

🔢 Basic Functions

• Arithmetic, brackets, fractions
• Percent, reciprocal, factor, π, roots
• Degree/Minute/Second (sexagesimal) functions

📐 Advanced Mathematics

• Exponential & logarithmic functions
• Trigonometric & inverse trig functions
• Hyperbolic functions
• Absolute values & power functions (square, cube, etc.)
• Random number/integer generation

📚 Higher‑Level Features

• Equation calculations (roots, etc.)
• Matrices & vectors
• Complex number calculations
• Integration and differential calculations
• Base‑n calculations (bin, oct, hex)
• Table generation functions

📊 Statistical Functions

• List‑based STAT editor (input and edit data sets)
• Basic statistics (mean, standard deviation)
• Regression analysis

📌 User‑Friendly Features

• Multi‑Replay: Recall and edit previous entries easily
• SOLVE Function: Solve equations numerically
• CALC Function: Quick evaluation of expressions for different values