Casio fx-991CW– Advanced Scientific Calculator with High-Res 4-Tone Display , Natural Textbook Display , 540+ Functions, Numeric Calculus, Matrix Solver , Ideal for Engineering, Science & Exams

NATURAL TEXTBOOK DISPLAY – View equations, fractions, and symbols exactly as they appear in textbooks for better comprehension and reduced errors.HIGH-RESOLUTION 4-TONE DISPLAY – Enhanced screen with quad-tone shading improves visibility and makes cursor tracking easy when writing and editing expressions.MEMORY & MATH CATALOG – Store and recall up to 9 variables containing integers, computations, and functions. Memory persists between sessions—an educator-requested feature. Access 47 constants, 40 conversions, advanced math functions, and more through the intuitive Math Catalog.540 ADVANCED FUNCTIONS – Perform numeric integration and differentiation, 4x4 matrix operations, spreadsheet-style data viewing, and more.QR FUNCTIONALITY & DURABLE DESIGN – Scan QR codes to graph results on ClassPad.net; includes rounded keys and a non-slip hard case for classroom or exam use.