This is how I see numbers in my head. I visualize them but not as a line. This spiral is a best guess as to where specific numbers are.
In reality, this curve isnt smooth but has lots of "bumps" and smaller features. There are also areas where the curve just kind of dissapears, around certain numbers. One of the lowest numbers that lies off-curve is 13. Because of this, for example, I have problems with any calculations that result in 13. If you ask me what 8+5 is, I have to think about it for quite a while until I try to by sheer memory and forget doing the counting. (Even as I typed this, I stopped to think "Is 8+5 really 13??")