A calculator is a device that can be used to make many different types of mathematical calculations, so there are many different types of calculators to handle the different functions. The designs and sizes of calculators vary based on what they are to be used for. Some calculators are designed for specific purposes, such as different trades or businesses, while others can be used just for basic mathematical calculations, like addition and multiplication.
The abacus was one of the first mathematical devices to be used, and it is simply a series of beads or stones that represent numbers. It wasn’t until 1623 that the first calculating machine was designed by Wilhelm Schickard, which was made to calculate astronomical tables. In 1645, Blaise Pascal designed his own calculator, called the Pascaline, which was used to add and subtract. The Pascaline was designed to reduce his workload of doing long computations by hand. The device was expensive and complicated, and calculating machines would not be ready for commercial use until the 19th century.
For the first half of the 20th century, mechanical adding machines were the main types of calculators used. These devices used keys, cranks, gears, and other components mostly to add and subtract — multiplication and division were done with multiple additions or subtractions. The latter half of the 20th century saw electronic technology advance from vacuum tubes to transistors, and this led to the creation of the wide array of handheld calculators that are in use today. The most basic kind of electronic calculator today is the pocket calculator, which in its simplest form can be solar powered and used to do most standard math problems, the results of which show up as a row of numbers on an LED screen.
While still remaining relatively small, scientific and graphing calculators are much more advanced than more simple calculators, and they are used primarily in the areas of science, mathematics, engineering and physics. These machines can have an entire screen rather than just a row of numbers that can display multiple calculations at once. With graphing calculators, data can be shown on the screen in the form of different types of graphs. Similarly, financial calculators are designed to do computations that are primarily needed in the world of finance and money. Examples of math that a financial calculator can be used for are interest rate conversions, amortization, and calculation of interest in loans, savings, and leasing.
Some types of calculators can be accessed through a computer and are designed to perform very specific functions. Most of these are available in several forms on the Internet, one example of which is a pregnancy calculator. In this type, the user inputs a small amount of information in order to find out a pregnant woman’s due date, among other key pregnancy information. Other online calculators can calculate the amount of calories a person should eat every day, a student's estimated grade point average, or even a person's age in dog years.