Abstract: The use of the punctuation marks “～”and “—” in sci-tech periodicals must be standardized.The punctuation mark “～” is used to reflect the number range,and “—”is used to join place names or location nouns.In English papers,the range of serial number is expressed by en dash “-” or by “from…to…”.When describing the range of variable value,if there exist two variables in the same value range,then it is briefer to use the mathematical operators respectively or the symbol of interval.

Key words: number range, serial number range, symbol, value range, suggestion