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# 小数

Decimal \[ˈdesɪml] Fraction

* 用point连接整数部分(the integral part)与小数部分，如zero/nought point two six。
* 精确到3个有效数字，correct to three significant figures。
* 精确到小数点后2位，correct to two decimal places。
* 四舍五入，rounding up or down，举例如下：
  * If the spreadsheet column is not wide enough to show all available decimal places, then the spreadsheet will round the number to the available column width.
  * Some items vary from month to month, like the phone bill for example, so track the amounts for a few months, take an average, and round up to the nearest $10.
  * Lastly, it stores the cleaned up and rounded value in the database.