Casio FX-991ES Plus Scientific Calculator

casio FX-991ES Plus Scientific Calculator is a high-performance, non-programmable scientific calculator designed for students, educators, and engineering professionals. It features 417 built-in mathematical functions, including numerical integration, differential calculus, matrix calculations, vector operations, and complex number calculations. Equipped with Casio’s Natural Textbook Display (Natural-V.P.A.M.), it renders fractions, roots, and formulas exactly as they appear in standard textbooks. The unit operates using two-way power (solar energy with an LR44 battery backup) and includes a protective slide-on hard case.