"Dont round if null" within the same script

"Dont round if null" within the same script

This is the script that I'm currently using. 
  1. input.Amount_1 = temp.Amount_1.round(0);
I would only like to invoke this expression if temp.Amount_1 != null

I have (10) amounts to do this to, so writing an if and else function for each one would be cumbersome. Is there a more simple function that will only round the number if not null ?