Abacus (The counting Machine)

The abacus is an ancient calculating machine. Thissimple apparatus is about 5,000 years old and is thought tohave originated in Babylon. As the concepts of zeroandArabic number notation became widespread,basic mathfunctions became simpler,and the use of the abacus dimin-ished. Most of the world employs adding machines,calcu-lators,and computers for mathematical calculations,buttoday Japan,China,the Middle East,and Russia still usethe abacus,and school children in these countries are oftentaught to use the abacus. In China,the abacus is called asuan pan,meaning counting tray. In Japan the abacus iscalled a soroban. The Japanese have yearly examinationsand competitions in computations on the soroban.Before the invention of counting machines,peopleused their fingers and toes,made marks in mud or sand,put notches in bones and wood,or used stones to count,calculate,and keep track of quantities. The first abaciwere shallow trays filled with a layer of fine sand ordust. Number symbols were marked and erased easilywith a finger. Some scientists think that the term abacuscomes from the Semitic word for dust,abq.

A modern abacus is made of wood or plastic. It isrectangular,often about the size of a shoe-box lid. With-in the rectangle,there are at least nine vertical rodsstrung with movable beads. The abacus is based on thedecimal system. Each rod represents columns of writtennumbers. For example,starting from the right and mov-ing left,the first rod represents ones,the second rod rep-resents tens,the third rod represents hundreds,and soforth. A horizontal crossbar is perpendicularto therods,separating the abacus into two unequal parts. The moveable beads are located either above or below thecrossbar Beads above the crossbar are called heaven pushed up to the crossbar. Number two would require two earth beads. For number five, only one heaven bead would to be pushed to the crossbar. The number six would require one heaven (five units) plus one earth (one unit) bead. The number 24 would use four earth beads on the first rod and two earth beads on the second rod. The number 26 then, would use one heaven and one earth bead on the first rod, and two earth beads on the second rod. Addition, subtraction, multiplication, and division can be performed on an abacus. Advanced abacus users can do lengthy multiplication and division problems, and even find the square root or cube root of any number.

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Why do the Indian telecom operators offer their services with 28 days validity, not 30 days?😡😡

Here telecom operator are very clever, b ecause telecom operators want to earn money of 13 months instead of 12 months. Let do the calculation and find out why telecom operators are offering 28 days validity. Each month they get 2 days more, therefore in a year they get additional 24 days. There are 7 month which has 31 days so they get additional 7 days.Now in case of February ,it has only 28 days not 30. So the total number of days they get are=24+7-2=29 days. So if you recharge 12 times then more 29 days are left in a year.🤔🤔 Means for another 29 days you have to recharge from that telecom operator.😫😫 So you have to recharge 13 times in a year instead of 12 times in a year. So telecom operators provide 28 days validity only. First one telecom operator started and then another telecom operators also understood this concept and they also applied 28 days validity both in data packs and voice packs.😱😱😱

20 Interesting science fact (PART 1)

1/ The speed of light is generally rounded down to 186,000 miles per second. In exact terms it is 299,792,458 m/s (metres per second - that is equal to 186,287.49 miles per second). 2/ It takes 8 minutes 17 seconds for light to travel from the Sun's surface to the Earth. 3/ October 12th, 1999 was declared \\"The Day of Six Billion\\" based on United Nations projections. 4/ 10 percent of all human beings ever born are alive at this very moment. 5/ The Earth spins at 1,000 mph but it travels through space at an incredible 67,000 mph. 6/ Every year over one million earthquakes shake the Earth. 7/ When Krakatoa erupted in 1883, its force was so great it could be heard 4,800 kilometres away in Australia. 8/ The largest ever hailstone weighed over 1kg and fell in Bangladesh in 1986. 9/ Every second around 100 lightning bolts strike the Earth. 10/ Every year lightning kills 1000 people. 11/ In October 1999 an Iceberg the size of London broke free...

A brief history of the Morse code

££) In the early nineteenth century, all of the essential components necessary to construct an electrical communication system had been discovered. The most important of these were the battery by Volta, the relationship between electric current and magnetism by Oersted, and the electromagnet by Henry. It now remained for someone to find a practical method to combine these technologies into a working communication system. ££)Some commercial electrical communications systems existed in Europe as early as the 1830s. A classic example of this is the English ‘Needle Telegraph’. The needle telegraph required two or more lines to form a complete circuit. It was relatively slow and the design of the transmitting and receiving instruments was complex. Something simple and efficient was needed. ££)The Morse system of telegraphy was invented by Samuel Finley Breese Morse (an American painter and founder of the National Academy of Design in New York) in the 1840s ...

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