Regular Expression + Aritmetical Expression

Is it possible to combine a regular expression with a aritmetical expression? For example, taking a 8-numbers caracter sequece and casting each output of a grep, comparing to a constant.

THX!

Sure, no problem. But I was not able to understand the problem well enough to cite an example. Can you be a little more specific?

yeah if u could be more specific by giving out an example of wht u want to do... i'm sure tht would be good enough to help u out and frankly spking i don't see any problem in wht u want to do... i'm sure it shd be possible