From ancient times, there has been a need for man to know basic arithmetic operations. From using his hands to an abacus to a slide rule and now, a modern-day calculator, man had gradually discovered the need to use a device to calculate as there is only so much a person can count on his or her fingers. Here, we will be looking at the greatest invention for arithmetic purposes.
Several present-day calculators are powered by electricity. Engineers and Engineering students use the more portable calculators that are battery-powered. The Slide Rule, a primitive calculator, was typically used before 1970. It was made of a slat of wood known as the Slide that could be moved in and out of a reinforced pair of Slats. The slide and slats are both calibrated with numerical scales. There is an adjusted transparent sleeve known as the Cursor that was used for alignment of the scale numerals. This primitive calculator did not require an electrical power source, but it did not give precise results every time. Also, to become knowledgeable with this calculator, you would have to climb a learning curve.
The abacus, which must be the most primitive and oldest calculator, is still in use in certain regions in the Far East. How the abacus works is using beads to indicate numbers, it does not require a power source. The beads are arranged in parallel rows and are moved either up or down to indicate the arithmetic operations. A skilled abacus user can calculate as fast as a modern-day battery-powered calculator user.
With the advancement of calculators during the 70s, there was an added feature of calculating for variables or unknown values. These calculators were called the first personal computers. Present-day personal computers still perform these operations as many of them are fitted with a virtual calculator application that when open looks like a hand-held calculator. The buttons are selected by clicking and pointing (or tapping the screen if the computer has a touchscreen feature).
Theoretically, a modern-day computer calculator works with binary numbers. Its added advantage is that its memory capacity is larger than that of a hand-held calculator. In practice, a computer is more than just a calculator as it performs other functions and actions that do not involve the use of a calculator.