The Casio fx-3600P (1983) is a programmable scientific calculator Key Specifications: Type: Programmable Keys: 39 Precision: 10 Logic: Algebraic Display type: LCD (liquid crystal) Length: 133mm Width: 71mm Thickness: 9mm Power Source:CR2025 3V cell The Casio fx-3600PV (1989) is a programmable scientific calculator Key Specifications: Type: Programmable Keys: 44 keys Display type: 10-digit LCD with indicators Power Source:Solar and 1.5V battery (e.g., LR44 cell) Functions: Scientific, statistical (SD), regression (LR), base-N (Binary, Octal, Decimal, Hexadecimal), integral calculations, and programming (Learn Mode). Input Method: V.P.A.M. (Visually Perfect Algebraic Method) for easier algebraic input Features: Auto power-off, program area indicators (P1, P2) Functionality Highlights: Programming (LRN mode): Allows users to write and execute short programs for repetitive tasks. Modes: Includes modes for normal calculation, programming, statistics, base-N math, and integrals. Units: Supports degree, radian, and grad angular units. This calculator was a popular model for students and professionals needing advanced scientific and basic programming capabilities in a compact, dual-powered device. The calculators are in good condition withsome user traces. The calculators will be packed carefully.