1. Looking at the arrangement rules horizontally: each line goes from left to right, which line is it currently in? It starts from the number 1 to the current line number, multiplied by the current line number respectively, and increases from left to right.

2. Looking at the arrangement law vertically: each column is from top to bottom, which row it is currently in, the current column number is multiplied by the current row number, and the number increases from top to bottom.

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China used the "99 formula" earlier. Now "99 multiplication formula" begins with "one by one gets one" and ends with "99.8 1". In ancient times, it was the other way around, starting with "99.8 1" and ending with "one for one".

Because the first two words of the formula are "99", people call it "99" for short. As early as the "Spring and Autumn Period" and "Warring States Period", "99 Ride Songs" had become popular.

The ancient western civilizations Greece and Babylon also invented the multiplication table, but it is more complicated than the 999 table. There are more than 1700 Greek multiplication tables invented by Babylon, and they are not complete enough. Because they worked hard to calculate multiplication and division before 13 century, people who can divide large numbers will be considered as experts in mathematics.

In March of 20 15, after the multiplication table of 1999 was introduced into Britain, it was difficult to recite the formula because of different languages. The British version may be changed to "12× 12 multiplication table" after one lesson and one practice.