If you want to enter numeric values as HEX numbers, you can quote HEX numbers with single quotes and a prefix of (X), or just prefix HEX numbers with (0x). A HEX number string will be automatically converted into a numeric value, if the expression context is a numeric value. Here are some good examples:
SELECT X'10' + 16 FROM DUAL;
32
SELECT 0x1000 + 0 FROM DUAL;
4096