1. Repetition: How many times a Roman numeral symbol is repeated means several times this number. For example, "three" means "3"; XXX stands for "30".
2. Right plus left minus: symbols representing large numbers are attached to the right of symbols representing decimals, indicating that Osuka is on decimals, such as "VI" for "6" and "DC" for "600". The symbol representing big numbers is accompanied by the symbol representing small numbers to the left, indicating the number of big numbers minus small numbers, such as "IV" for "4", "XL" for "40" and "VD" for "495".
3. Add a horizontal line: add a horizontal line to the Roman numeral, indicating that it is 1000 times that number. For example, ""means "15000" and "165000".
In ancient China, notation was also very important. The oldest notation is found in Oracle Bone Inscriptions and Zhong Ding, but it is difficult to write and identify, so it is not used by future generations. In the Spring and Autumn Period and the Warring States Period, production developed rapidly. In order to meet this need, our ancestors created a very important calculation method-calculation. The chip used in the calculation is made of bamboo sticks and bones (Figure 9). Arranged according to the specified length order, which can be used for counting and calculation. With the popularization of calculation, the arrangement of calculation and preparation has become the symbol of calculation. There are two types of calculation and arrangement, horizontal and vertical, both of which can represent the same number.
If you want to express 197 1, you can put it as shown in figure 1 1.
It is clear from the absence of "10" in the calculation code that the calculation strictly follows the decimal system from the beginning. Numbers exceeding 9 digits will enter one digit. The same number, a hundred in a hundred, Wan Li has ten thousand. This calculation method was very advanced at that time. Because the decimal system was really used in other parts of the world at the end of the 6th century. But there is no "zero" in digital calculation, and there is a vacancy when it meets "zero". For example, "6708" can be expressed as "┴ ╥". There is no "zero" in the number, which is easy to make mistakes. So later, some people put copper coins in the blank to avoid mistakes, which may be related to the emergence of "zero". However, most people believe that the invention of the mathematical symbol "0" should be attributed to Indians in the 6th century. They use black dots first (? 6? 1) means zero, and then gradually becomes "0".
Speaking of the appearance of "0", it should be pointed out that the word "0" appeared very early in ancient Chinese characters. But at that time, it didn't mean "nothing", just "bits and pieces" and "not much". Such as "odd", "sporadic" and "odd". "105" means that there is a score of 100. With the introduction of Arabic numerals. "105" is pronounced as "105", and the word "zero" corresponds to "0", which means "0".
If you look closely, you will find that there is no "0" in Roman numerals. In fact, in the 5th century, "0" was introduced to Rome. But the Pope is cruel and old-fashioned. He doesn't allow any use of "0". A Roman scholar recorded some benefits and explanations about the usage of "0" in his notes, so he was summoned by the Pope and executed the punishment of "Zn" so that he could no longer hold a pen and write.
But no one can stop the appearance of "0". Now, "0" has become the most meaningful digital symbol. "0" can mean "No" or "Yes". For example, temperature does not mean that there is no temperature; "0" is the only neutral number between positive and negative numbers; The power of 0 of any number (except 0) is equal to1; 0! = 1 (the factorial of zero is equal to 1)
In addition to decimal system, in the early stage of the germination of mathematics, there were many numerical decimal systems, such as five, binary, ternary, seven, eight, decimal, hexadecimal, twenty, hexadecimal and so on. In the long-term practical application, decimal has finally gained the upper hand.
At present, the internationally used numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0 are called Arabic numerals. In fact, they were first used by ancient Indians. Later, Arabs integrated ancient Greek mathematics into their own mathematics, and this simple and easy-to-remember decimal notation spread all over Europe, gradually evolving into today's Arabic numerals.