Convert string to decimal Oracle database

Question

I intended convert data type string to decimal in Oracle data base and i get this error:

ORA-01722: número no válido 01722. 00000 - "invalid number" *Cause: The specified number was invalid. *Action: Specify a valid number

Code:

TO_NUMBER('5.0') AS numero

CAST('5.0' AS NUMBER) AS numero

Answer 1

select TO_NUMBER('5.0') from dual;

select NLS_NUMERIC_CHARACTERS
 from v$nls_parameters;

 --There must be '.' in value filed to run above query