using System;

​

public static partial class DoubleExtensions

{

    public static double RoundUP(this double valor, int decimalDigits = 2)

    {

        if(decimalDigits <= 0)

            decimalDigits = 2;

        return (Math.Ceiling(valor * Math.Pow(10, decimalDigits)) / Math.Pow(10, decimalDigits));

    }

    public static decimal RoundUP(this decimal valor, int decimalDigits = 2)

    {

        if(decimalDigits <= 0)

            decimalDigits = 2;

        var retorno = DoubleExtensions.RoundUP((double)valor, decimalDigits);

        return Convert.ToDecimal(retorno);

    }

}

public class Program

{   

    public static void Main()

    {

        var valor = 2.5m;

        int digits = 2;

        Console.WriteLine($"C# Default  = \t {valor}");

        Console.WriteLine($"C# Round    = \t {Math.Round(valor, digits)}");

        Console.WriteLine($"C# Round MidpointRounding.ToEven    = \t {Math.Round(valor, digits, MidpointRounding.ToEven)}");

        Console.WriteLine($"C# Round MidpointRounding.AwayFromZero  = \t {Math.Round(valor, digits, MidpointRounding.AwayFromZero)}");      

        Console.WriteLine($"C# RoundUP  = \t {valor.RoundUP(digits)}");

        return;

    }

}