No.1 (minus) is a sign made by a horizontal line when the crew uses the water in the bucket to indicate the water consumption of the day, so as to indicate the reduction of water consumption. Later, "-"was used as the minus sign of subtraction.

When the crew refilled the used bucket, they added a vertical line to the original "-"mark, so they added "+".

1489, the symbols of-and+appeared for the first time in the reading materials related to arithmetic written by German Weidemann.

163 1 year, Eliot of England used the symbol "×" (multiplication) in his own Key to Mathematics, and he used the oblique cross as the multiplication symbol. The symbol "⊙" has two meanings (except). First of all, the symbol represents the division in fractional form, with "?" Added the next one. ",respectively, represent the numerator denominator. Another way of saying this is that when expressed as a fraction, the "? "is a symbol used to distinguish it from"-".

Leibniz, a famous German scientist, thinks that although the symbol "×" is widely used, it is easily confused with the unknown "X". Therefore, he advocated using the symbol ""instead. He also advocated using ":"instead of "symbol. However, these two symbols have not been realized so far.