1.Math.Round：四舍六入五取偶
Math.Round(17.475728155339805, 2, MidpointRounding.AwayFromZero)=17.48
Math.Round(0.0) //0
Math.Round(0.1) //0
Math.Round(0.2) //0
Math.Round(0.3) //0
Math.Round(0.4) //0
Math.Round(0.5) //0
Math.Round(0.6) //1
Math.Round(0.7) //1
Math.Round(0.8) //1
Math.Round(0.9) //1
说明：对于1.5，因要返回偶数，所以结果为2。
2.Math.Ceiling：向上取整，只要有小数都加1
引用内容
Math.Ceiling(0.0) //0
Math.Ceiling(0.1) //1
Math.Ceiling(0.2) //1
Math.Ceiling(0.3) //1
Math.Ceiling(0.4) //1
Math.Ceiling(0.5) //1
Math.Ceiling(0.6) //1
Math.Ceiling(0.7) //1
Math.Ceiling(0.8) //1
Math.Ceiling(0.9) //1
说明：例如在分页算法中计算分页数很有用。
3.Math.Floor：向下取整，总是舍去小数
引用内容
Math.Floor(0.0) //0
Math.Floor(0.1) //0
Math.Floor(0.2) //0
Math.Floor(0.3) //0
Math.Floor(0.4) //0
Math.Floor(0.5) //0
Math.Floor(0.6) //0
Math.Floor(0.7) //0
Math.Floor(0.8) //0
Math.Floor(0.9) //0