The Casio Fx-991Es Plus Is A Sophisticated Scientific Calculator Featuring A Natural Textbook Display That Shows Mathematical Expressions As They Appear In Textbooks. This Blue Model Combines Advanced Functionality With User-Friendly Operation, Making It Ideal For Students And Professionals In Mathematics, Science, And Engineering. Key Features: • Natural Textbook Display For Clear Visualization Of Mathematical Expressions • Over 250 Built-In Mathematical Functions • Solar Powered With Battery Backup • 10+2 Digit Display (10-Digit Mantissa + 2-Digit Exponential) • Multi-Replay Function For Formula Recall And Editing • Statistical Calculations And Data Analysis Capabilities • Durable Plastic Keys With Clear Layout The Calculator Comes With A Protective Slide-On Hard Case And Features A High-Contrast Lcd Screen For Excellent Visibility. It Supports Various Mathematical Operations Including Trigonometry, Statistics, Calculus, And Engineering Calculations. The Device Includes Memory Functions, Constant Calculations, And Unit Conversions. Its Compact Size (Approximately 77Mm X 162Mm X 11.5Mm) Makes It Portable While Maintaining A Comfortable Key Size For Operation.