SQL & PL/SQL :: Add Variable Number Of New Columns To Existing Table Temp

I want to add a variable number of new columns to an existing table temp (with column provided).

Example:

NewColumnNo = 4
-> the columns shall be named rate_1, rate_2, rate_3 and rate_4
-> the values shall be = Column / NewColumnNo

The result shall be like this:

create table temp_res (prodid integer, rate_1 number, rate_2 number, rate_3 number, rate_4 number);
insert into temp_res values(1, 0.25, 0.5, 0.75, 1);
insert into temp_res values(2, 0.25, 0.5, 0.75, 1);
insert into temp_res values(3, 0.25, 0.5, 0.75, 1);
insert into temp_res values(4, 0.25, 0.5, 0.75, 1);
insert into temp_res values(5, 0.25, 0.5, 0.75, 1);
insert into temp_res values(6, 0.25, 0.5, 0.75, 1);
insert into temp_res values(7, 0.25, 0.5, 0.75, 1);
insert into temp_res values(8, 0.25, 0.5, 0.75, 1);
insert into temp_res values(9, 0.25, 0.5, 0.75, 1);