Error message help

I have developed a questionnaire using excel.
As the interviewee answers a question, the following equation returns an corrsponding number (1-5);
=VLOOKUP(Scale,Score,2,FALSE)

My problem is that if the question is not answered or left clear(which will happen a lot), the vlookup returns #N/A.

So a series of data returned from this function might be 2,3,5,1,#N/A,3,#N/A. I want to average and get a max/min from this data treating the #N/A as a 0.

Thanks,

Rich