# Online calculator

The calculator is easy to use. It is a free online calculator for quick calculations.
You will find below the different keys of the calculator and their function :

: subtract
: multiply
: divide
: reset ("C" for "Clear")
: the negative sign. Allows you to make a negative number. Enter the number then (-).
Example :
To perform the operation -5 + 2 = -3, you must type :
"5" then "(-)" then "+" then 2 then "="

: 1 divide by the number typed
Example :
To perform the mathematical calculation 1/5, you must type the following operation on the keys of the calculator :
"5" then "1 / x" then "=", this gives the result 0.2

The keys to use the calculator memory are :
Example :
M + : addition of data in memory
M- : subtract data from memory
MR : recall of the number recorded in the memory

Let's take an example of using a calculator with a number in memory :
To calculate "3 x 8 - 6 x 2 + 12 x 3 =", use the keys below of the calculator :
"3" then "X" then "8" then "=" then "M+"
"6" then "X" then "2" then "=" then "M-"
"12" then "X" then "3" then "=" then "M+"
"MR" to display the result
In our example the result displayed is 48. Indeed, 3 x 8 - 6 x 2 + 12 x 3 = 24 - 12 + 36 = 48

: percentage

## Definition of a calculator

A calculator is a machine designed to perform mathematical operations.
It makes it possible to simplify and make the calculations more reliable.

## History of calculators

It is difficult to define a starting point in the history of calculators.
Indeed, Humanity counts from the beginning. We originally counted with our fingers.
Calculation tables were used in Mesopotamia, then the invention of the mechanical calculator.
The first electronic calculators were invented in the 1960s.

The invention of the first true calculator is credited to Blaise Pascal (1623 - 1662). Blaise Pascal is a French mathematician and inventor. He invents a calculator in around 1642 : the Pascaline (or the Pascal’s calculator). He continued to make improvements to his design and built around fifty Pascaline machines in total.

In the course of the 1970s, handheld electronic calculators are invented. We can name three companies that have marked this moment in the history of the calculator : Texas Instruments (United States of America), Casio (Japan) and Hewlett Packard (USA).

Below are some examples of electronic calculators:
- Texas Instruments TI 2500 Datamath : this was the first commercial calculator produced by Texas Instruments (TI) and introduced in mid-1972.
- Casio fx-10 : this was the first scientific calculator created by Casio and launched in 1974.
- HP-35 : this was the first hand-held scientific calculator launched in 1972 by Hewlett Packard (HP).

## Four rules of math

The four basic math operations are addition, subtraction, multiplication and division.

## Basic math symbols

 Symbol Symbol Name Meaning or Definition Example + plus sign addition 2 + 3 = 5 - minus sign subtraction 5 − 3 = 2 X times sign multiplication 3 × 4 = 12 / division slash division 12 / 3 = 4 = equals sign equality 8 = 3 + 5

## Calculator

Calculators combine inputs using electronic components called logic gates. Like all other electronic devices, calculators work by processing information in binary form. A calculator is a combination of millions of logic gates arranged in particular ways that operate on numbers and produce results with lightening speed. By pressing a button, you complete a circuit underneath the rubber, which sends electrical impulses through a circuit board below. Pocket calculators can do all these things and more using tiny electronic switches called transistors. An electronic calculator is a portable electronic device used to perform calculations. TI 2500 Datamath was introduced in mid-1972 and was the first commercial calculator produced by Texas Instruments.