Draw an arc counterclockwise from the upper end of Tian Zige vertical line (about 1/3). When the pen tip touches the top of Tian Zige (about 3/7), continue to draw an arc counterclockwise. When the pen tip touches the left boundary of Tian Zige (about 1/2), it still draws an arc counterclockwise. At this point, the nib continues to draw an arc counterclockwise through the middle horizontal line of Tian Zige until it returns to the starting point.

Data expansion:

Arabic numerals (also called Indian numerals) consist of ten counting symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 * *. Arabic numerals were first invented by ancient Indians, then spread to Europe by Arabs, and then modernized by Europeans. People think it was invented by Arabs, so people call it "Arabic numerals".

Origin:

Around 500 A.D., with the rise and development of economy and caste system, Punjab in the northwest of Indian subcontinent has been in a leading position in mathematics.

Astronomer Ayepihite made a new breakthrough in simplifying numbers: he recorded the numbers with a grid. If there is a symbol in the first grid, such as a point representing 1, then the same point in the second grid represents ten, and the point in the third grid represents one hundred. In this way, not only the digital symbols themselves, but also their position order is of great significance.

Later, Indian scholars introduced the symbol zero. It can be said that these symbols and representations are the old ancestors of Arabic numerals. Arabic numerals Indian numerals In the 3rd century A.D., ancient Indian scientist Baghdad invented Arabic numerals.

The oldest meter is about 3 meters. In order to imagine the number "4", it is necessary to add 2 and 2. 5 is 2 plus 2 plus 1, and 3 is 2 plus 1. Handwriting with five fingers for the number 5 and hands with ten fingers for the number 10, which is probably too late.

This principle is actually the basis of mathematical calculation. Rome's count is only numbers within V (that is, 5), and numbers within X (that is, 10) are composed of V (5) and other numbers. ⅹ is a combination of two ⅴ, and the same digital symbol has different quantities according to its position relationship with other digital symbols.

In this way, the concept of digital position began, and this important contribution in mathematics should be attributed to the ancient residents of the two river basins. Later, the ancients improved on this basis and invented nine symbols 1, 2, 3, 4, 5, 6, 7, 8 and 9 to represent numbers.