Charles Babbage's differential and analytical engines were also earlier calculating machines.

Whose name is as follows.

1. ABACUS ( Thousands of years ago ) 
2. Napier Bones ( 1617 ) 
3. Pascaline or Pascal’s Calculator (1642 )
4. Stepped Reckoner (1694 )
5. Arithmometer ( 1820 )
6. Comptometer ( 1887 ) and Comptograph (1889)

1. ABACUS
            ABACUS is known to be the first mechanical calculating device. The word ABACUS is derived from the Greek word ABAX. It means a table or board covered with dust. This device was used to count, and subtract by moving the beads up and down. Abacus is made up of a wooden frame in which rods were fitted across with round beads sliding on the rod. it is divided into two parts call heaven and earth.
          Although abacus is not mechanical, it was one of the most widely used calculating device for many years
          Which was invented by the Chinese, thousands of years ago?

2. Napier Bones ( 1617 ) 
          As the necessity demanded, scientists started inventing better calculating devices. in this process Jone Napier's of Scotland invented a calculating device, in the year 1617 called the Napier Bones. it was made of ivory strips, Each strip was used to multiply and divide numbers. 

3. Pascaline or Pascal's Calculator ( 1642 ) 
        A French Mathematician Blaise Pascal in  1642 invented a device called Pascaline. It could and subtract numbers. In this device, the multiplication was done by repeated additions, and a division was done by repeated subtractions. 

4. Stepped Reckoner (1694 )
       The Stepped Reckoner invented by Gottfried von Leibniz. it was the first machine to calculate all the four arithmetic operations. it was also the first machine to use a cursor and therefore has a memory for storing the first operand Leibniz built two-stepped Reckoners.

5. Arithmometer ( 1820 ) 
       The Arithmometer was patented by Thomas de Colmar in 1820 and was the first successful mechanical calculator to be used in offices. form 1851 to 1890. the Arithmometer was the only type of mechanical calculator in production. The machine can perform addition and subtraction direction and can perform long multiplication and division.

6. Comptometer ( 1887 ) and comptograph ( 1889 ) 
       The comptometer was the first mechanical calculator with a keyboard. The keyboard consists of 8 columns of 9 keys. the comptometer is very similar to Pascal's Calculator but can perform faster calculations due to its keyboard. it can perform addition, subtraction, and long multiplication and division. Some computers have keys for special purposes such and currency and weight.