About the retention of decimal places in a database

In the database, sometimes we may need to process 1 data, such as 4 rounds 5, directly omitted after a few bits, etc., in fact, it is very simple, there are ready-made functions, we just need to apply on the line:
select round (10.98 * 10) / 10 from dual; - 4 5 in
select ceil (10.63 * 10) / 10 from dual; Let's take the upper limit
select floor (10.68 * 10) / 10 from dual; Let's take the limit