double m= 50;
double n= 100;
Response.Write((m/ (m+ n)).ToString("0%"));
Response.Write((m/ (m+ n)).ToString("0.00%"));
Response.Write((m/ (m+ n)).ToString("P"));
Response.Write((m/(m+n)).ToString("0.000%"));
Response.Write((m/ (m+ n)).ToString("P3"));