SQL & PL/SQL

Dear friend

i have insert monday to sunday check box value into Operating_days Column as concatenation.

MON =1
TUES =2
WED =3
THU =5
FRI =6
SAT =6
SUN =7


Using computation after submit i have concatinate it and insert in to OPERATING_DAYS Column into table.
example :if i check MON AND WED AND FRI THEN concatenate value insert into table 136


:P6_MON||:P6_TUS||:P6_WED||:P6_THR||:P6_FRI||:P6_SAT||:P6_SUN

Now problem is How to extract 1 into Mon,2 into Tue and 3 into wed etc . from Operating days.

How can i do this .