class Sequel::SQL::NumericExpression

in a numeric value in SQL.
Subclass of ComplexExpression where the expression results

def +(ce)

Always use + for + operator for NumericExpressions. 
def +(ce)
  NumericExpression.new(:+, self, ce)
end

def sql_number

Return self instead of creating a new object to save on memory. 
def sql_number
  self
end