About AS2.0 (type mismatch)

since now i have used AS 1.0, but my new script requires AS 2.0
the problem is that i have this old AS1.0 codeline

digit = duration-parseInt((elapse-begin)/1000);

and when i publish it with AS 2.0 it says: Type mismatch.

i’m new to AS2.0, what should i do with that line?