The origin of the decimal point is urgent! Fast! 5

The origin of the decimal point.

A long time ago, there was no decimal point. When people write decimals, if they write decimal parts, they write the decimal part down one square and slightly smaller than the integer part. In the 16th century, the German mathematician Rudolf used a vertical line to separate integer and decimal parts.

In the 17th century, the English mathematician Sharper used a comma, "," as the dividing point between the integer part and the decimal part. In the late 17th century, Indian mathematicians first used small dots when studying decimals"to separate the integer part from the decimal part, and it is only at this time that the decimal point is truly born.

Magic decimal point.

The decimal point may seem small, but it does a lot of things. If it doesn't want to run around at will, the size of the number will change. Move the decimal point to the right (left) by one, two, three... The original number is enlarged (reduced) by 10 times, 100 times, 1000 times...

Decimal points and tragedy.

On June 30, 1970, the famous Soviet cosmonaut Feradimir Komarov returned home in the Soyuz-1 spacecraft after 23 days on the space station. However, when the plane returned to the atmosphere, no matter how it operated, it could not open the parachute, and as a result, it crashed near the landing base, and the cosmonaut hero Komarov was killed. The incident with Soyuz-1 was caused by the fact that a decimal point was omitted during the ground inspection.

Let's remember the tragedy of the decimal point! We must not be negligent in the study of mathematics, otherwise it will lead to serious consequences.

Follow me to learn the tricks.

1. The decimal point should be in the lower right corner of the single digit of the integer part. The decimal point divides the decimal into two parts, and it is the mark of the boundary between the integer part and the decimal part in the decimal number.

2. When the initial decimal is used, it is easy to be affected by the integer reading, and the decimal part is read according to the integer reading, such as: it should be read as 0.705, not as 0.705 according to the integer reading.

A long time ago, there was no decimal point. When people write decimals, if they write the decimal part, they will lower the decimal part by one box, omitted.

The first one expresses the decimal number in the form that is common in the world today (.).The German mathematician Kravis (1537 1612) began to use the decimal point as the divider between the integer and the decimal part in his book The Astrolabe (1593).

The decimal point, a mathematical symbol, is used to separate the integer and decimal parts in the decimal system.

The origin of the decimal point.

China has used decimal notation since ancient times, and some practical units of measurement also use the decimal system, so it is easy to produce decimal fractions, that is, the concept of decimals. The first to put this concept into words was Liu Hui in the Wei and Jin dynasties. In the process of calculating pi, he used 7 units, such as ruler, inch, minute, centimeter, millimeter, second, and sudden; Smaller units are no longer named, but collectively referred to as "decimals".

By the Song and Yuan dynasties, the concept of decimal had been further popularized and more clearly represented. Yang Hui's "Daily Algorithm" (1262) contains a mantra for the conversion of two catties: "One seek, the next six two five; Two seeks, abdicate one, two, five", i.e., 1 16 0 0625;2/16＝0�125。

The words "spacer" and "abdication" here already have the meaning of indicating the position of the decimal point. Qin Jiushao bet the unit under the chips that represent the unit digits of the integer part, for example: —indicates that the inch is the world's earliest decimal notation.

In Europe and Islamic countries, the ancient Babylonian decimal system had long been dominant, and some classical scientific works used the decimal system, so the concept of decimal decimal was not developed for a long time. Alcashi (?) in Central Asia in the 15th century1429) was the first person outside of China to apply decimals.

European mathematicians did not begin to consider decimal numbers until the 16th century, most notably the Dutchman Steven (1548 1620), who explicitly expressed the law in his book On the Decimal System (1583). For example, write it as: 5 7 1 4 or 5,7'1''4'''。

The first person to represent decimals in the form that is common in the world today was the German mathematician Kravis (1537-1612), who began to use the decimal point as the dividing point between the integer and the decimal part in his book The Astrolabe (1593).

China adopted it more than 300 years earlier than Europe.

The decimal point, although small, is very useful. We must not ignore this small symbol at any time. Because of this inconspicuous mistake, mankind has caused one tragedy after another.

It can be said that "the difference is a millimeter, and the error is a thousand miles". In 1967, the crash of the former Soviet Union "Soyuz-1" caused irreparable damage. The immediate cause is that a decimal ...... is ignored when checking on the groundled to the loss of hundreds of millions of dollars in wealth, and mankind also lost the life of a space hero--- Komarov!

The decimal point is expressed by Liu Hui in the Wei and Jin dynasties. At that time, in the process of calculating pi, Liu Hui used seven units, such as ruler, inch, minute, centimeter, second, and sudden, and the numerical units smaller than the flickering unit were no longer named, and were collectively called micro, which is now called the decimal point.

Since ancient times, China has adopted the decimal system of notation, this algorithm is easier to produce decimal fractions, that is, the prototype of the decimal point, to the Song and Yuan dynasties, the concept of decimal point has been further popularized and expressed, for example, Yang Hui's "daily algorithm" mentions the formula of partition and abdication, where the position of the decimal point is expressed.

The decimal point is a mathematical notation written ". .It is used in the decimal system to separate the integer part and the decimal part of the point, which appeared and developed in ancient China, and in Europe, ancient Babylon and other countries since ancient times, the decimal system is usually used, this algorithm is not easy to produce decimal points, so the concept of early local decimal points has not been developed.

Categories: Education Science.

Problem description: The origin of the decimal point.

Analysis: It took a long time and the efforts of many people to create a method of counting physical objects.

Like the current decimal counting method, if you look at the entire history of mankind, it can be regarded as a rather late thing.

No matter how large the number, it can be easily expressed by counting in decimal terms with only ten numbers from 0 to 9.

So, why should there be a decimal point?

Because magnify integers by 2x, 5x, 10x....The numbers obtained are still integers, so there is no problem with using the original integer expression; But if you divide the integer into 1 2 , 1 5 , 1 10 ...The obtained number is not necessarily an integer, so if you use the original integer, you will not be able to express it completely, so you have to create a decimal number to make up for the deficiency. Because decimals are also used.

Ten numbers from 0 to 9 are depresented, so a separate symbol, the decimal point symbol, must be used to identify the decimal and integer parts to make it easier to distinguish between them.

In the past, the symbol of the decimal point was written in various ways. For example, there are at least three ways to write .

1,1234 1丨Rang Cong Mo 1234 1 1 2 3 4

Later, the mathematician Khwarazmi solved the above problem by inventing the decimal point.

There are some interesting facts about the mathematician Khwarazmi:

The testament of mathematician Khwarazmi, whose wife was pregnant with their first child. "If my dear wife helps me to bear a son, my son will inherit two-thirds of the inheritance, and my wife will receive one-third; If it is a daughter, my wife will inherit two-thirds of the inheritance, and my daughter will receive one-third. "。

Unfortunately, before the child was born, the mathematician died. After that, what happened bothered everyone even more, his wife helped him give birth to a pair of dragon and phoenix fetuses, and the problem occurred in the content of his will.

How can a mathematician give his estate, his sons, and his daughters, in accordance with his will?

1. China has used decimal notation since ancient times, and some practical units of measurement also use decimal system, so it is easy to produce decimal fractions, that is, the concept of decimals. The first to put this concept into words was Liu Hui in the Wei and Jin dynasties.

2. In the process of calculating pi, he used 7 units such as ruler, inch, minute, centimeter, millimeter, second, and sudden; Smaller units are no longer named, but collectively referred to as "decimals".

3. In the Song and Yuan dynasties of Yugaochang, the concept of decimal has been further popularized and more clearly expressed. Yang Hui's "Daily Algorithm" (1262) contains a mantra for the conversion of two catties: "One seek, the next six two five; Two seeks, abdicate one, two, five".

4. The "spacer" and "abdication" here already contain the meaning of indicating the position of the decimal point. Qin Jiushao bet the unit under the chips that represent the unit digits of the integer part, for example: - Zhen Pai — indicates that the inch is the world's earliest decimal notation.

The decimal point is a mathematical symbol. Writing"." is used to separate integer and decimal parts in the decimal system.

In the English decimal reading, the decimal point is read as:"point", the integer part is read according to the general reading of cardinal words, and the decimal part is read separately.