1 /* 字段 */  2 Math.E;             //2.71828182845905  3 Math.PI;            //3.14159265358979  4   5 /* 静态方法 */  6 Math.Abs;           //绝对值  7 Math.Acos;          //反余弦  8 Math.Asin;          //反正弦  9 Math.Atan;          //反正切 10 Math.Atan2;         //反正切, 两参数 11 Math.BigMul;        //int32 * int32 = int64 12 Math.Ceiling;       //取 >= 的最小整数 13 Math.Cos;           //余弦 14 Math.Cosh;          //双曲余弦 15 Math.DivRem;        //取商和余数 16 Math.Exp;           //求 e 的指定次幂 17 Math.Floor;         //取 <= 的最大整数 18 Math.IEEERemainder; //求余 19 Math.Log;           //自然对数 20 Math.Log10;         //以 10 为底的对数 21 Math.Max;           //取大 22 Math.Min;           //取小 23 Math.Pow;           //求幂 24 Math.Round;         //就近舍入, 可指定精度 25 Math.Sign;          //取符号, 或返回 -1、0、1  26 Math.Sin;           //正弦 27 Math.Sinh;          //双曲正弦 28 Math.Sqrt;          //平方根 29 Math.Tan;           //正切 30 Math.Tanh;          //双曲正切 31 Math.Truncate;      //取整 32  33  34  35  36 练习: 37 -------------------------------------------------------------------------------- 38   39 //Truncate()、Floor()、Ceiling() 40 protected void Button1_Click(object sender, EventArgs e) 41 { 42     double n1 = Math.Truncate(Math.PI); // 3 43  44     double n2 = Math.Floor(2.5);        // 2 45     double n3 = Math.Floor(-2.5);       //-3 46  47     double n4 = Math.Ceiling(2.5);      // 3 48     double n5 = Math.Ceiling(-2.5);     //-2 49  50     TextBox1.Text = string.Concat(n1, "\n", n2, "\n", n3, "\n", n4, "\n", n5); 51 } 52  53 //就近舍入(取偶) 54 protected void Button2_Click(object sender, EventArgs e) 55 { 56     double n1 = Math.Round(0.5);  // 0 57     double n2 = Math.Round(1.5);  // 2 58     double n3 = Math.Round(2.5);  // 2 59     double n4 = Math.Round(3.5);  // 4 60     double n5 = Math.Round(-0.5); // 0 61     double n6 = Math.Round(-1.5); //-2 62     double n7 = Math.Round(-2.5); //-2 63     double n8 = Math.Round(-3.5); //-4 64  65     TextBox1.Text = string.Concat(n1, "\n", n2, "\n", n3, "\n", n4, "\n", n5, "\n", n6, "\n", n7, "\n", n8); 66 } 67  68 //四舍五入 69 protected void Button3_Click(object sender, EventArgs e) 70 { 71     double n1 = Math.Round(0.5, MidpointRounding.AwayFromZero);  // 1 72     double n2 = Math.Round(1.5, MidpointRounding.AwayFromZero);  // 2  73     double n3 = Math.Round(2.5, MidpointRounding.AwayFromZero);  // 3 74     double n4 = Math.Round(3.5, MidpointRounding.AwayFromZero);  // 4  75     double n5 = Math.Round(-0.5, MidpointRounding.AwayFromZero); //-1 76     double n6 = Math.Round(-1.5, MidpointRounding.AwayFromZero); //-2 77     double n7 = Math.Round(-2.5, MidpointRounding.AwayFromZero); //-3 78     double n8 = Math.Round(-3.5, MidpointRounding.AwayFromZero); //-4 79  80     TextBox1.Text = string.Concat(n1, "\n", n2, "\n", n3, "\n", n4, "\n", n5, "\n", n6, "\n", n7, "\n", n8); 81 } 82  83 //指定小数位数(0..28)的舍入 84 protected void Button4_Click(object sender, EventArgs e) 85 { 86     double n1 = Math.Round(3.126, 2);  // 3.13 87     double n2 = Math.Round(3.124, 2);  // 3.12 88  89     double n3 = Math.Round(3.125, 2);  // 3.12 90     double n4 = Math.Round(3.135, 2);  // 3.14 91  92     double n5 = Math.Round(3.125, 2, MidpointRounding.AwayFromZero);  // 3.13 93     double n6 = Math.Round(3.135, 2, MidpointRounding.AwayFromZero);  // 3.14 94  95     TextBox1.Text = string.Concat(n1, "\n", n2, "\n", n3, "\n", n4, "\n", n5, "\n", n6); 96 } 97  98  99 100 asp.net 系统中math数学函数  能够很快的帮我们进行运算！

转：http://www.cnblogs.com/ruicky/archive/2012/06/19/2554821.html