[C 98][1]
=================

This is my first time Golfing so here goes;

 #include <stdio.h>
 int i,j,k;int main(int,char**v){for(;i<7;(j+=(v[1][i]-'0')*("31"[i++%2]-'0'))); 
 for(;(k+=10)<j;);putchar("FT"[v[1][7]-'0'==(k-j)%10]);}

usage:

 ./a.out XXXXXXXX

where XXXXXXXX is a zero padded string, it will return either an F or a T

this is 155 chars long in total the main.cpp file is 4.0k


 [1]: https://en.wikipedia.org/wiki/C_(programming_language)