going to try to explain this joke

from my ci:
a norwegian man is interviewing for a job. the interviewer doesn't like him so he thinks up a difficult question to ask: I want you to get me to say the number 9 without using any letters, numbers or words, here's a pen and paper
norwegian: draws a picture of 3 trees lined up next to each other.
interviewer: explain
norwegian: tree + tree + tree = 9
interviewer: ok, now get me to say the number 99 without using any letters, numbers or words.
norwegian: draws some spots on each of the trees.
interviewer: ok, what's that
norwegian: well dirty tree + dirty tree + dirty tree = 99
interviewer: frustrated, ok, now 100.
norwegian: draws a little thing next to each of the trees.
interviewer: ok, what's that
norwegian: well a little doggie came along and pooped next to each of the trees, so dirty tree and a turd + dirty tree and a turd + dirty tree and a turd = 100, do i get the job?


in a team meeting about all of our patients:
a little background first: the dr that my ci works with is a quite, to the point kind of guy.
we (PT, OT, speech, case mgr, dr, nursing) were discussing a patient that has earned the nickname mr grouchy, simply because he is grouchy and never wants to work out...i could go into more detail here but i'll spare you. durring our discussion each and every staff member reporting had the same explaniation: pt doesn't want to work, tells you to go away, is full of excuses..... and out of nowhere the quite dr says: "so you want me to prescribe him motivation pills?" the entire room had a nice long laugh... just wanted to write this down becuase it made me laugh on a day that was difficult, but understand if it isn't very funny as being there and seeing all the events unfold probally made it funny.