Numeric is the abstract class for numbers. In Ruby, operations are possible among different numerical classes.
Operations and comparison methods (+, -, *, /, <=>), etc. are defined in a subclass. For increased efficiency, methods identical to the Numeric method may also be redefined in a subclass.
Returns self.
Returns self, negated.
This method is defined by the binary operator - in 0 - self.
Returns the absolute value of self.
Returns the smallest integer equal to or greater than self (i.e., the ceiling).
Returns the largest integer that does not exceed self (i.e., the floor).
Returns true when self is an integer.
Returns the integer closest to self.
Discards the decimal point and all digits after it.