In Chinese typesetting, periods are divided into full-width periods and half-width periods. A full-width period is a period that occupies the width of a full-width character, while a half-width period is a period that only occupies the width of a half-width character. In Chinese typesetting, it is generally more appropriate to use full-width periods, because full-width periods are more in line with Chinese typesetting habits and norms, more beautiful and generous, and more conducive to reading. At the same time, the use of full-width periods can also avoid typography confusion or unsightly when mixed with English and other half-width characters. But in mathematical formulas, half-angle period is also commonly used, because a large number of symbols and spaces are needed in mathematical formulas. Using a full-width period will make typesetting look crowded and unsightly, while a half-width period is more appropriate. Therefore, it is suggested to use half-angle period in mathematical formula.