[tex]\bf \stackrel{\stackrel{\textit{\Large 6 units}}{\cfrac{}{}}}{\stackrel{P}{\boxed{-7}}\rule[0.35em]{2em}{0.25pt}\boxed{-6}\rule[0.35em]{2em}{0.25pt}\boxed{-5}\rule[0.35em]{2em}{0.25pt}\boxed{-4}\rule[0.35em]{2em}{0.25pt}\boxed{-3}\rule[0.35em]{2em}{0.25pt}\boxed{-2}\rule[0.35em]{2em}{0.25pt}\stackrel{D}{\boxed{-1}}}[/tex]