Pos Ui?

[lord_icon]

I am trying to develop a simple POS UI (Point Of Sale).
How can I calculate 2 ten pences for 27? How do I get to the 2 * 10 ? I know I can use MOD for the remainder after division. Though I need some help.
TIA

 

[ChrisPaulson]

i = 27.

r = mod( 20 ).

h = i - r.

r will contain 7.

h will contain 20.