Modify value - type duration

[Andreas.Schmidl@googlemail.com]

Hello!

I started programming in Ada for about a month. Because of that my
knowledge isn't really good, but will be better every day ;-)
I have a problem to modify a fixed point value  (type duration).

I want to cut all before the point. Example:
---------------------------------------------------
var1 : duration := 12.345;
var2 : duration;

var2 := cutIt(num => var1);
---------------------------------------------------

var2 is now 0.345. To implement the function "cutIt" I tested an idea.
I converte var1 to an integer:

---------------------------------------------------
function cutIt(var : duration) return duration is

tempvar : integer;

begin
	tempvar := integer(var);
	return (var - duration(tempvar));

end cutIt;
--------------------------------------------------

But this isn't a solution. Converting to integer with integer(...)
round the value.
Example:
12.345 ---> 12
12.854 ---> 13

Is there any other more elegant and functional solution in Ada?

Thanks for your help!

Best regards!

Andreas