Simple addition

I have collect totals in text boxes vars are:
var 1stTotal
var 2ndTotal
var 3rdTotal

I need to total these textboxes answers into a totalScore.
I have the following, but it puts the 1st total and undefined for the others
ie 100%undefinedundefined

How do I get this to add up the numbers?

totalScore = 1stTotal + 2ndTotal + 3rdTotal;

also how do I get percent to round off to 2place, like 33.33333% to 33%

Thanks