In the west, it is generally believed that decimals were invented by Belgian mathematician Steven. In On Decimals (1585), he wrote 5.9 12 as 5 ◎ 9 1 1223, and systematically discussed the concept and usage of decimals. His symbol was inconvenient to use, so someone soon improved it. 1592 or so, Bigel in Switzerland only wrote a symbol, 0, below the single digit to separate the integer part from the decimal part. German mathematician kravis was the first person to use the decimal point in the modern sense. He used the decimal point in 1593. But until the end of 19, the decimal notation was still very confusing, such as 2.5:
2,5; 2'5; 2、5; 2∠5; 2△5; 2.5 and so on. There are about ten kinds of notation.
Even in modern times, decimal points can be divided into two notation methods: continental European school and Anglo-American school. The former uses commas, while the latter insists on dot.
In fact, before Steven invented the decimal point, China, India and Central Asia had already used decimal fractions, that is, decimals.
In the 3rd century A.D., the idea of decimal was used in Liu Hui's Notes on Nine Chapters of Arithmetic in Wei and Jin Dynasties. For example, when talking about the square root, if the square root can't open a single digit, we should continue to open it and find its "difference". The denominator of the first number is 10, and the denominator of the second number is 100 until a sufficiently accurate approximation is obtained. Of course, according to Liu Hui's method, 3. 14 16 should be written as 31104/100/1000 6//kloc-0.
In the Southern and Northern Dynasties and the Song and Yuan Dynasties, the symbols as shown in the figure were widely used in calendars.
These symbols are much better than Steven's symbols more than 300 years later.
Alkasi in Central Asia is the first country in the world to use decimals except China. His usage is embodied in his book The Keys to Arithmetic (1427).
Whether in the East or the West, the understanding of decimals has evolved for hundreds or even thousands of years.