Converting Data Type Problem

1

So I’m importing this file called tbox.txt and in that file it has a variable, num, which equals 3. Now when I run the debug window, it comes back as num = “3”. So its a string. so I do num=num-0 to make it a number instead of a string. And it doesn’t work so I do a trace on num and it comes back as undefined… which is what I dont understand, how can it be “3” and undefined at the same time… please help…