| You can write a normal mathematical expression with the following operators: | 
		| num1 + num2 | Add num1 and num2 | 
		| num1 - num2 | Subtract num2 from num1 | 
		| num1 * num2 | Multiply num1 and num2 | 
		| num1 / num2 | Divide num1 by num2 | 
		| num1 ** num2 | Return num1 to power of num2 | 
		| num1 ? num2 | Return num2 if num1 is non-zero, otherwise return 0 | 
		| num1 : num2 | Return num2 if num1 is zero, otherwise return num1 | 
		| - num - Negate num | 
		
| A name followed by a value makes a function call. Currently only the following builtin functions are available: | 
		| sqrt num | Return square root of num | 
		| sin num | Return sinus of num | 
		| cos num | Return cosinus of num | 
		| tan num | Return tangent of num | 
		| abs num | Return absolute value of num |