The Casio x-991ES PLUS 2nd Edition is an improved version of the popular x-991ES PLUS scientific calculator. It features a natural textbook display that shows expressions and results as they appear in textbooks, making it easier to understand and learn. The calculator has 417 functions, including basic arithmetic, fractions, complex numbers, matrices, vectors, calculus, statistics and more. You can also use the calculator to solve equations, find roots and perform numerical integration and differentiation. The calculator is solar-powered with a battery backup and has an auto power-off function to save energy. The calculator has a sleek and ergonomic design and comes with a hard case to protect it from scratches and damage.