13 Calculators

An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.

A calculator watch is a digital watch with a built-in calculator, usually including buttons on the watch face. Calculator watches were first introduced in the 1970s and continue to be produced, despite falling from their peak popularity during the 1980s. The most dominant brands in the end was the Casio Databank series and Timex.

A euro calculator is a very popular type of calculator in European countries that adopted the euro as their official monetary unit. It functions like any other normal calculator, but it also includes a special function which allows one to convert a value expressed in the previously official unit to the new value in euros, or vice versa. Its use became very popular within the population and commerce of these countries especially during the first few months after adopting the euro.

Expensive Desk Calculator by Robert A. Wagner is thought to be computing's first interactive calculation program.

A financial calculator or business calculator is an electronic calculator that performs financial functions commonly needed in business and commerce communities. It has standalone keys for many financial calculations and functions, making such calculations more direct than on standard calculators. It may be user programmable, allowing the user to add functions that the manufacturer has not provided by default.

A formula calculator is a software calculator that can perform a calculation in two steps:Enter the calculation by typing it in from the keyboard. Press a single button or key to see the final result.

A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science, engineering, and mathematics. They have completely replaced slide rules in traditional applications, and are widely used in both education and professional settings.

Specula Melitensis Encyclica was a 1638 work by the Jesuit scholar Athanasius Kircher. It was printed in Naples by Secundino Roncagliolo and dedicated to Giovanni Paolo Lascaris, Grand Master of the Knights of Malta.

The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments (TI). They are differentiated from most other TI graphing calculators by their computer algebra system, which allows symbolic manipulation of algebraic expressions—equations can be solved in terms of variables, whereas the TI-83/84 series can only give a numeric result.

TI-BASIC 83,TI-BASIC Z80 or simply TI-BASIC, is the built-in programming language for the Texas Instruments programmable calculators in the TI-83 series. Calculators that implement TI-BASIC have a built in editor for writing programs. While the considerably faster Z80 assembly language is supported for the calculators, TI-BASIC's in-calculator editor and more user friendly syntax make it easier to use. TI-BASIC is interpreted.

The TI-Nspire is a graphing calculator made by Texas Instruments which was released in July 2007. The original TI-Nspire was developed out of the TI PLT SHH1 prototype calculator, the TI-92 series of calculators released in 1995, and the TI-89 series of calculators released in 1998. The TI-Nspire features a non-QWERTY keyboard and a different key-by-key layout compared to its predecessors. The TI-Nspire allows users to swap out the existing removable keypad with a functional copy of the TI-84 Plus series keypad. The TI-Nspire series I/O has a connector for the TI-Nspire Lab Cradle, another that serves as a connector for TI's wireless network adapter, and a Mini-USB connector for transferring data. The TI-Nspire series is available with and without a computer algebra system.