Tanner Playing A Little Ditty

Tanner sat down to the piano yesterday and started plunking out this tune...

Sound familiar?  I'm not sure how exactly he knows this particular song.  I don't ever play it in the car, but I'm sure I do hum it occasionally (or a lot) since this is what we are singing next in choir.  The notes aren't all there, but bless his little heart for having the patience and fortitude to sit at a piano and try to plunk out the tune.