Returning a value with decimals

Question

I am passing some numbers to a method that should return a decimal value but the method is rounding the decimal up to a whole number.  How can I keep the decimals from disappearing?:

       private decimal calcArea(int n, int w, int l, int h)
        {
            decimal dArea = (n * (((w*2)+(l*2))*h+(2*w)*l)) / 144 ;
            return dArea;
        }

Thanks,

cj