The Casio FX-991ES PLUS-2 is a highly versatile scientific calculator designed to meet the needs of students, professionals, and anyone requiring advanced mathematical capabilities. Its extensive features encompass arithmetic, trigonometric, logarithmic, and exponential functions, alongside scientific notation, fractions, and statistical functions. With a clear high-resolution display, intuitive button layout, and Natural Textbook Display allowing for expression input and viewing akin to textbooks, its 417 functions, including equation solving, integration, and differentiation, offer comprehensive mathematical utility. PRODUCT SPECIFICATIONS: Manufacturer: Casio Number of digits: 10 + 2 digits Weight: 95 g Dimensions: 161.5 × 77 × 11.1 mm Power source: AAA battery