CASIO fx-991ES PLUS Scientific Calculator.

The CASIO fx-991ES PLUS Scientific Calculator is an advanced calculator designed for students and professionals across various scientific and engineering fields. It boasts 417 Functions and features the NATURAL V.P.A.M. (Visually Perfect Algebraic Method) display, which allows mathematical expressions to be displayed exactly as they appear in textbooks (e.g., fractions, roots, and integrals). This capability significantly aids in understanding and checking calculations. Key features include an Easy Menu Function for quick access to various modes and calculations, along with the ability to perform complex functions like integration, differentiation, equation solving, and matrix calculations. The Display Expression same as Textbook feature makes it an essential tool for high-level academic work.