A delegate acts on behalf of a method. It is the representative of this method. The delegate below represents all methods that return a Boolean and have a single argument of type Integer:

delegate bool MathDelegate(int x);

To demonstrate this generality, we can create a void method that takes two arguments, the delegate itself and its single argument:

void AboutNumber(MathDelegate Func, int x)
{
    if (Func(x)) //Invoke the delegate.
        Response.Write(" is ");
    else
        Response.Write(" is not ");
}

Now AboutNumber() can run all of the following methods:

bool IsEven(int x) 
{
    if (x % 2 == 0) 
        return true;
    else
        return false;
}

bool IsPrime(int x)
{
    for(int i = 2; i > (x /2); i++)
        if (x % i == 0) 
            return true;                                        
        return false;
}

So, because of delegates a variable number of methods can be funneled through one method.