1namespace utility
 2{
 3    static public class Mathematics
 4    {
 5        static public decimal subtract(this decimal right, decimal left)
 6        {
 7            return right - left;
 8        }
 9
10        static public decimal add(this decimal right, decimal left)
11        {
12            return right + left;
13        }
14
15        static public decimal multiply_by(this decimal right, decimal left)
16        {
17            return right*left;
18        }
19
20        static public decimal divided_by(this decimal right, decimal left)
21        {
22            return right/left;
23        }
24    }
25}