The following are the eight mechanical calculators that existed prior to the invention of modern computers. 1. The abacus (ca. 2700 BC) Although the abacus is not mechanical, it was a popular calculating instrument for many years. It can calculate sums by adding up columns of beads on wires, just like today's digital watches. 2. The quadrant (16th century) A quadrant is a device used to measure angles between 90 degrees and 180 degrees. It consists of **four arms** attached to a central point, with each arm ending in a small ball. By placing the quadrant over an angle marked on a surface being measured, the observer can see which arm is raised next when the balls drop into place.

3. The slide rule (17th century) A slide rule is a calculator used for arithmetic and scientific calculations. It includes a flat strip of wood or metal with scales printed along one edge; a slider mechanism that can be moved along the scale to select a range of numbers to use as input; and a pointer attached to the other end of the slider that can be positioned to show the result of the calculation.

4. The pocket watch (early 18th century) The pocket watch was a significant advance over **the slide rule** and remains useful today for determining times and dates. It uses **a clockwork mechanism** that can store energy while performing a calculation and then release it when needed.

Before modern computers, there were eight amazing mechanical calculators.

Prior to the twentieth century, most computations were performed by people. Early mechanical gadgets for assisting humans with digital computations, such as the abacus, were known as calculating machines or calculators (and other proprietary names). The machine operator was referred to as the computer. In 1770, Joseph-Marie Jacquard designed and built a mechanized loom that could weave different patterns of material into one piece of cloth. This invention is considered the first computing machine.

During the Renaissance, mathematicians began to make progress on some of their greatest challenges through the development of mathematics. They developed many new techniques and ideas but they needed a way to keep track of their work which wasn't yet possible due to the lack of any sort of **recording device**. As we know today, paper was invented in China around 220 A.D., so it's natural to assume that it was also used for mathematical notes back then. However, there are no records of this happening and it's estimated that it didn't become popular until **about 600 A.D.** when it was introduced into Europe via the Arab world.

The first true computer may be said to have been created by **Charles Babbage**. He proposed an analytical engine for calculating values of functions at given points which he called "fiduciary figures". It consisted of a number of interlocking parts: cylinders with pegs attached to them, holes with notches, adding machines with racks and balls, and so forth.

The abacus, an ancient calculating instrument, is said to have begun as a "counting box" in Babylon circa 2400 B.C.E. It was the first calculator in the world, and modern versions are still in use today. The Chinese invented the first electric calculator in 200 C.E., but it was the Indian who developed the technique of printing numbers on beads with colors that were used to calculate by size.

The first mechanical calculator was created by **John Napier** in 1621. He called it an "abacus" because it worked based on columns of beads, which were very similar to those used today. The modern computer was invented in Germany in 1945, but it wasn't until much later that computers became affordable for **most people**. In 1976, the first personal computer was sold for $10,000. In 1996, Microsoft launched its Internet Explorer web browser, which is currently the most popular browser in the world.

Abacus calculators were once common tools in schools across Asia. They were used to teach arithmetic concepts such as fractions and decimals. Abacus drills were also used by Asian merchants to practice addition, subtraction, and multiplication using **ceramic tokens**.

Today, abaci are used by scientists to perform **precise calculations** during experiments. They're also useful for counting time in cultures all over the world.

Abacus The abacus is the oldest known calculating instrument. The abacus, which was used as **a basic computing device** for conducting mathematics, most likely originally existed in Babylonia (now Iraq) approximately 5000 years ago. It was later adopted in India and China.

The first written reference to an abacus appears in a book called "Mathematics for the Physicist" by Jordan's student Omar Khayyam. The book was written about 1150 AD but it wasn't published until about 1310. So, the abacus used by Khayyam was probably not very different from modern models. However, it is possible that he used a modified version of the abacus with more rods instead of beads.

The first true calculator was invented in Germany around 1514 by **Johann Müller**. He called his invention "calculating machine". Today, we know this as **a clockwork computer** because it contained parts that functioned like computers today. For example, it had numbers you could add together, multiply by **a single number**, divide by a number, and test if a number was equal to another number.

Müller's invention was one of the first devices that could perform calculations without human intervention. His machine used gears, levers, and wheels to calculate numbers that it then displayed on its face in the form of letters.