Plus42 is an advanced scientific programmable calculator that builds on the popular Free42 calculator. Free42 is a complete re-implementation of the HP-42S scientific programmable RPN calculator, known for its reliability and functionality. Plus42 takes this foundation and enhances it with additional features and improvements.

One of the key enhancements in Plus42 is the inclusion of algebraic expressions modeled after those used on the HP-27S and HP-17B/19B calculators. This makes it easier for users who are familiar with these calculators to transition to Plus42 and perform complex calculations effortlessly.

Another notable feature in Plus42 is the attached units and unit conversions, which are modeled after those used on the HPseries calculators. This feature allows for seamless conversion between different units, making it a powerful tool for engineers, scientists, and students alike.

Plus42 also introduces directories for more organized storage of programs and variables. This helps users keep their calculations and data organized, making it easier to retrieve and manage their work.

The calculator boasts a larger display with 8 rows and 22 columns (131x64 pixels) by default, providing ample space for viewing complex equations and calculations. Users also have the flexibility to resize the display to suit their preferences.

In addition to its advanced mathematical capabilities, Plus42 offers time value of money and amortization schedules, making it a valuable tool for financial calculations. It also supports two-dimensional plotting of functions, allowing users to visualize mathematical functions, zoom in and out, pan across the plot, and even find integrals and roots from points on the graph.

With its extensive feature set and user-friendly interface, Plus42 is a powerful scientific calculator that caters to the needs of professionals, students, and enthusiasts alike.