Math Calculators
Basic Calculator

Basic Calculator

This online calculator performs basic mathematical operations like addition, subtraction, division, and multiplication. You can use the calculator to find percentages and taxes.

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Table of Contents

  1. Basic calculator
  2. Directions for use
  3. Calculating percentages
  4. Calculation examples
    1. Taxation
    2. Calculating the area of a house
  5. Calculator: the history of development
    1. Abacus
    2. The Antikythera mechanism
    3. Leonardo da Vinci's counting machine
    4. Schickard's calculating clocks
    5. Blaise Pascal's counting machine
    6. Leibniz’s calculator
    7. The Colmar Arithmometer
    8. Calculators in the XX Century
    9. Contemporary Calculators

Basic Calculator

Basic calculator

The online calculator allows you to perform the standard mathematical operations quickly. This standard calculator performs the following procedures:

  • addition,
  • subtraction,
  • multiplication,
  • division,
  • raising to the power of 2,
  • taking a square root,
  • identifying, adding, and subtracting a percentage.

The calculator takes integers or decimal numbers as inputs. While the operations listed above are sometimes easy to perform mentally, a simple calculator can be handy for working with large numbers and decimals.

Directions for use

Below are the special commands included in the calculator:

  • mc stands for "Memory Clear", you press it when you want to clear the calculator's memory.

  • mr stands for "Memory Recall", press it when you want to recall the number currently stored in the calculator's memory. If the calculator memory is empty, mr will return zero.

  • m- stands for "Memory Minus." When this button is pressed, the number currently on the screen will be subtracted from the number stored in the calculator's memory.

  • m+ stands for "Memory Plus." Similarly to m-, when m+ is pressed, you will add the number on the screen to the current number in the calculator's memory.

  • C.E. is an abbreviation for "Clear Entry" and should be used to remove the current entry. Note that this button only becomes visible after you have made at least one entry and the screen is not empty.

  • A.C. stands for "All Clear." Press this button when you want to delete all previous entries. For example, if you would like to calculate 8-3=? but you have accidentally entered 8-4, you can press C.E. before hitting the = sign, which will only delete the last entry – 4 – while keeping the first entry – 8 – intact. Then you can press 3 and hit the = sign to get the answer to the required question. Hitting A.C. will delete all inputs, including the 8. Note that hitting A.C. does not clear the memory; you need to press mc for that.

  • R2 stands for "Round to 2 decimals." For example, if, after some calculations, you end up with a number that looks something like this: 3.98124567, you can press R2 to approximate it to a simpler-looking number, which in this case will look like this: 3.98.

  • R0 stands for "Round to 0 decimals." In our previous example, rounding 3.98124567 to 0 decimals would result in the following number: 4.

Suppose the resulting number is very large or small after you perform some calculations. In that case, the calculator will use the scientific e-notation to display the answer. For example, if the answer is 0.00000007, the calculator will return 7e-8, which stands for 7×10⁻⁸.

Calculating percentages

When calculating a percentage of a certain number, pressing the % sign will automatically display the percentage value as a decimal. For example, if you need to calculate 20% of 75, you should enter 75 × 20%, which will automatically change the value from 20 to 0.2. To see the final answer, press the equal sign, which will result in 15 on the screen, as 15 is 20% of 75.

The calculator also allows you to add or subtract a certain percentage of a value from the value itself. Also, pressing the % sign will automatically display the percentage value. For example, suppose you need to perform the following operation 60 - 15% after you press the % sign. The number will automatically change to 9, since 9 is 15% of 60. After pressing the equal sign, you will get the desired answer: 51.

Calculation examples


The calculator can be handy for quick calculations of sales tax. Let's say you need to calculate the total purchase price of an item with a price of $567 plus 6% sales tax. Enter 567 + 6% and press the equal sign. After you hit the % sign, you will see the value of the sales tax applied to this purchase (34.02), and after pressing the equal sign, you will see the final result: 601.02.

Sometimes, the final answer will contain more than 2 digits after the decimal point. You can press R2 to round it up to two decimals in such cases. This will give you the final price in dollars and cents.

In our previous example, if the sales tax were 6.6% instead of 6%, the value of the sales tax would be 37.422, and the final answer would be 604.422. To find the value in dollars and cents, press R2, which will return 604.42 on the screen. It means that the total price of the purchase will be 604 dollars and 42 cents.

Calculating the area of a house

Let's assume you need to calculate the area of your house to know how many floor panels you have to buy for the rooms. You know that one room has a length of 5 meters and a width of 3 meters, and the second room has a length of 4 meters and a width of 6 meters. You also know that the area of a room can be calculated as follows:

$$Area = Length × Width$$

Instead of finding the two areas separately and then adding the values, you can use the calculator to perform all the calculations at once. To do that, enter 5 × 3 =, to get the value of 15, which is the area of the first room. Then press m+ to add this number to the calculator's memory. Furthermore, enter 4 × 6 =, to get the value of 24, which is the area of the second room.

With 24 still on the screen, hit the plus sign + and mr, to add the value from the calculator's memory (15, the area of the first room) to the current value. Then hit the equal sign to get the final answer of 39. The area of both rooms adds up to 39 square meters.

Calculator: the history of development

The word "calculator" itself comes from the Latin "calculo", which means "to count," "to calculate." The origin of the name can also be linked to the word "calculus," which translates as "pebble." Initially, in ancient times, people used pebbles for counting.


The abacus was invented in ancient Babylon around the 3rd millennium B.C. It was the prototype of a counting machine.

Initially, the abacus was a board, ruled into lines or with indentations. Counting marks (stones, dice) moved along the lines or indentations. Later, modifications of the abacus appeared, where pebbles or bones for counting were put on rods.

When people moved all the pebbles on the first rod to one side, one pebble on the next rod was moved, showing the number of tens. The next rod already showed the number of hundreds and so on (at the same time, the tenth pebble in the first row shifted to the original position).

In some parts of the world, people used a variation of the abacus in the form of counting frames to settle accounts in stores and in bookkeeping until the 1980s and 1990s.

The Antikythera mechanism

The Antikythera mechanism is considered one of the oldest prototypes of the modern calculator. It was discovered at the beginning of the 20th century near the Greek island of Andikythera in a shipwreck. Scientists believe the mechanism may have been used in the second century B.C. The device helped calculate the motion of planets and satellites. The Antikythera mechanism could also add, subtract, and divide numbers.

Leonardo da Vinci's counting machine

In the diaries of Leonardo da Vinci, one can see the drawings of the first counting machine. The machine consisted of several rods with wheels of different sizes. Each wheel had cogs that allowed the device to work. Ten rotations of the first wheel led to one rotation of the second wheel, and ten cycles of the second wheel led to one complete rotation of the third wheel. Leonardo da Vinci was never able to build a working counting machine during his lifetime.

Schickard's calculating clocks

In 1623, German professor Wilhelm Schickard claimed to have invented the calculating machine. The machine could perform addition, subtraction, multiplication, and division. It was called the "calculating clock" because of the principle of the mechanism using gears. The Schickard calculating clock was the first mechanical device to perform four arithmetic operations.

Blaise Pascal's counting machine

In 1642, 19-year-old Blaise Pascal began developing a new counting machine. Pascal's father was a tax collector and had to deal with constant calculations. So, his son decided to create a device to make such work easier.

Blaise Pascal's counting machine was constructed as a small box containing many interconnected gears. The numbers needed to perform the four arithmetic operations were entered by turning the wheels. Within ten years, Pascal constructed about 50 copies of the machines, 10 of which he sold.

Leibniz’s calculator

In 1673, the German mathematician Gottfried Wilhelm Leibniz created a version of the calculator. The principle of operation was the same as that of Pascal's adding machine—gears and wheels. Leibniz added to this mechanism the innovation in the form of a stepped cylinder called the Leibniz wheel.

Despite the mechanical flaws of this device, it suggested possibilities for future calculator inventors. The stepped cylinder, invented by Leibniz, was used in many calculating devices for the next 200 years.

The Colmar Arithmometer

In the first half of the 19th century, Charles Xavier Thomas de Colmar created the arithmometer. This first commercially available calculating device could perform four arithmetic operations. The Arithmometer was based on Wilhelm Leibniz's calculator.

The De Colmar Arithmometer was a small iron or wooden mechanism with an automated counter. It could perform four arithmetic operations: addition, subtraction, multiplication, and division. The arithmometer could already handle thirty-digit numbers. The De Colmar Arithmometer had been produced for over 60 years (until 1915) and sold by more than 20 companies.

Calculators in the XX Century

In the late 1930s, the world was preparing for a new war. Gun makers needed guns with exact aiming to hit enemy targets.

One of the first devices to control anti-aircraft fire was the Kerrison predictor. It was a mechanical counting device that could calculate the pointing angle of guns based on target position, ballistic parameters of the weapon and ammunition, wind speed, and other conditions.

During World War II, the first fully electronic computer, Colossus, was created in Great Britain to decode intercepted enemy communications. The machine specialized exclusively in decoding, but it was programmable and even had an electronic display.

ENIAC was created in the fall of 1945, after World War II's end. It was originally designed for military purposes—to calculate firing tables. But it could also perform four basic arithmetic functions. The ENIAC was 1,000 times faster than electromechanical computers and could store ten-digit numbers in memory. It required 17,468 electronic tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors, and about 5 million hand-soldered connections.

The computer weighed about 27 tons and took up 167 square meters. ENIAC had been functioning until 1955 at the U.S. Army Ballistics Research Laboratory.

In 1961 came ANITA, the world's first fully electronic desktop calculator, developed by the British company Control Systems Ltd. The calculations were based on vacuum tubes. And the display used gas-discharge indicators. These early ANITA calculators were sold for about £355, which in today's money is about £4,800 ($8,000).

Canon, Mathatronics, Olivetti, SCM (Smith-Corona-Marchant), Sony, Toshiba, and Wang joined the calculator race.

In 1965, Wang Laboratories released the Wang LOCI-2 calculator with a logarithm calculation function.

The Toshiba "Toscal" BC-1411 used one of the earliest versions of RAM, made from circuit boards. The Olivetti Programma 101, introduced in late 1965, could read and write data on magnetic cards and print calculation results on a built-in printer.

The ELKA 22 calculator was developed by the Central Institute for Computing Technology in Bulgaria. It weighed 8 kilograms and was the world's first calculator that could extract the square root.

In 1967, Texas Instruments released the Cal Tech prototype. This calculator could add, subtract, multiply, divide, print the result on paper tape, and fit in the palm of your hand. In 1985, Casio released the Casio FX-7000G. It was a calculator widely regarded as the world's first graphing calculator available to the public. It was programmable and had 82 scientific functions.

Contemporary Calculators

Several companies mass-produced calculators with hundreds of models for various purposes at the end of the first decade of the 21st century. CASIO is the leader in the overall production of calculators. In 2006, CASIO announced its one billionth calculator.

Nowadays, we can easily access various calculators. Calculators can be divided into simple, engineering, accounting, and financial based on the target audience and characteristics. They can work with complex programs pre-built into the mechanism itself.

Thanks to programming languages, professionals can now write applications for specialized calculators and make them publicly available on the Internet. Mathematical, engineering, statistical, medical, fitness, financial, time, and conversion calculators are now available to everyone on their smartphone.