4936, what other ways can I express it?

4936, what other ways can I express it?

4936 can also be expressed by 9436.

Describe 4936 in words: A class holds activities, which just happens to be divided into four groups with nine people in each group. How many people took part in this activity?

Describe 9436 in words: A class holds activities, which are just divided into 9 groups with 4 people in each group. How many people took part in this activity?

The origin of multiplication

The multiplication methods of ancient Greece, ancient Egypt, ancient India and ancient Rome are complicated and inconvenient to remember. Because there is no carry system, in principle, you need an infinite multiplication table, so there is no 99 table. For example, the multiplication table of ancient Greece must list 7x8, 70x8, 700 x8, 700x8, 700x8, 700x8, 700x8 and 7000x8. In contrast, since the 99-99 table is based on the decimal system, 7x8=56, 70x8=560, 700x8=5600, 7000x8=56000, and only 7x8=56 is needed for one representation. There was no multiplication table in ancient Egypt. Archaeologists found that the ancient Egyptians calculated the product by repeated addition. For example, to calculate 5x 13, first get 26 from 13+ 13, then add 26+26=52, and then add 13 to get 65.

Ancient Babylonian arithmetic had a carry system, which made great progress compared with Greece and other countries. However, Babylonian arithmetic used a hexadecimal system. In principle, a multiplication table of "59x59" needs 59*60/2= 1770 items; Because the "59x59" multiplication table is too large, the Babylonians never used a "multiplication table" similar to the Jiujiu table. Archaeologists have never found the multiplication table of "59x59" similar to Jiujiu Table. But archaeologists found that the Babylonians used the unique 1x 1 = 1, 2x2 = 4, 3x3 = 9...7x7 = 49, ... 9x9 = 81...16x/kloc. To calculate the product of two numbers A and B, the Babylonians relied on their best algebra, axb=((a+b)x(a+b)-axa-bxb)/2. Such as 7x9 = ((7+9) x (7+9)-7x7-9x9)/2 = (256-49-81)/2 =126/2 = 63.

The ancient Mayans used the decimal system, which is the closest to the decimal system commonly used in the modern world. A multiplication table of 19x 19 has 190, which is more than three times larger than the 45 items in the Jiujiu table, but much simpler than the Babylonian method. But archaeologists haven't found any Mayan multiplication tables yet. Multiplication by multiplication table is not the inevitable result of carry system. Babylonia had a carry system, but instead of inventing or using the multiplication table of 99 tables, they invented the square table method to calculate the product. The Mayans' mathematics was the most advanced in the ancient civilization in the Western Hemisphere, and they used the decimal system, but they didn't invent the multiplication table. It can be seen that from the carry system to the multiplication table is a big step forward. China not only invented the decimal system, but also invented the Jiujiu Watch during the Spring and Autumn Period and the Warring States Period. Later, the East was introduced to Korea and Japan, and then spread to India and Persia in the west through the Silk Road, which became popular all over the world. Decimal system and nine tables are important contributions of ancient China to world culture. Multiplication in Greece and other countries is rarely used internationally.

Characteristics of Jiujiu Watch

General 1 and 99 tables only use 9 numbers from 1 to 9. 2. Jiujiu table contains the commutativity of multiplication, so only 8972 is needed, and "9872" is not needed. 9 times 9 has 8 1 product, and the 99 table only needs 1+2+3+4+5+6+7+8+9 =45 product. In the Ming Dynasty, abacus also had 99 tables with 8 1 product. The 99 table of 45 items is called small 99, and the 99 table of 8 1 item is called big 99. 3. The shortest multiplication table in the ancient world. Maya multiplication table must have 190, Babylon multiplication table must have 1770, and Egypt, Greece, Rome, India and other countries must have infinite multiplication tables; Only 45/8 1 item is needed for the 99 table. 4. There is rhythm when reading aloud, which is convenient for memorizing the whole table. 5. Jiujiu watches have existed for at least 3000 years. It was used for calculation from the Spring and Autumn Period and the Warring States Period, and was improved and used for abacus in the Ming Dynasty. The 99 standard is also the basic skill of elementary school arithmetic. People generally describe those who are good at calculating, calculating and planning as having a career in mind.