**Introduction**

At past ,Man used Sticks and Pabbles to count people and amimals, later counting was done on the fingers and the fact is that man has the ten fingers that led to the development of decimal number system. And the nation, trade, technology grew fast and more advance calculating aids were developed as time passed.

**Mechanical Calculating Era:**

**Using Finger:** In the stone age, there is no any counting methodology and they use finger as counting tools.

**Barter System:** Later people started barter systen which is the system of exchange where participants in the transection exchange goods instead of using money or other medium.

**Pebble Counting:** It is also used as means of calculating at past and many people use oe pabble for each transaction.

**Drawing Symbol:** People used to draw crude pictures or symbols on the walls or sand to counts number of killings of animals. It is less useful method. Later on, the advance form, **Tally Stick** was used as business transections. A line made on the stick used to record a transection and when the deal was completed, the stick was divided into two and each partner in the transection received half as a receipt.

**Abacus:** It is the earliest calculating device, which is used till now. **An Abacus is a calculating device made on a wooden frame with beads sliding on wires. **.

It consist of a rectangular wooden frame with parallel bars with beads strung on them. On moving the beads along the bars does counting.

**Napier's Bone:** A Scottish Mathematician named John Napier In 1614 AD made a set of rods to do simple multiplication. Number were carved on these rods called 'bones' The numbers were carved in such a way that by simple placing them side by side, products of large numbers could be easily obtained.

**Slide Rule:** An English Mathematician named William Oughtred combine the principle of logarithm and Napier's Bones to construct the Slide Rule. It consists of two scales one moving over each other.

**Pascal's Calculator:** A Franch Mathematician named Blaise Pascal In 1642 AD made made a simple mechanical calculator. It consisted of gears and wheels and registered number by rotating the wheel by one to ten steps. When the wheel is moved by ten units, the next higher digit wheel moved by one unit. This is useful for addition and subtraction but can't multiply and division.

**Leibniz Calculating Machine:** A German Mathematician named Gottfried Von Leibnitz In 1671 AD made a machine that could perform multiplication and division too. The machine of Leibnitz and pascal showed that machine could perform arithmetic.

**Jacquard's Punched Cards :** James Jacquard made a new invention in the weaving industry and he introduced a cardboard card with holes punched on it to guide the threads to produce a different patterns. It halps to managed to translate the instructions for patterns into cards containing punched holes .

**Charles Babbage:** A English Mathematician named Charles Babbage In 1671 AD made a machine that could perform multiplication and division too. The machine of Leibnitz and pascal showed that machine could perform arithmetic. It is also known as the world's first computer.

**Charles Babbage:** A English Mathematician named Charles Babbage In 1671 AD made a machine that could perform multiplication and division too. The machine of Leibnitz and pascal showed that machine could perform arithmetic.