Newer Version of Casio 991 EX & 4-times better resolution than Casio 991ES Plus for easier viewing of long expressions. Natural Textbook Display- Input and display fractions, powers, logarithms, roots, and other mathematical formulas and symbol just as they appear in textbooks. Colour coded keypad for easy key differentiation. Scientific Calculator with inbuilt QR Code function --Calculator can generate QR Code -- Useful from graphical visualization & accessing user manual using your smart phone.