The originate from Newfoundland and Labrador, Canada BTW I can't believe no one knew this I'm 12 and I knew this off the top of my head
If you say something "off the top of your head," it just means you have not really thought carefully about it or rehearsed it or anything. You're just saying the first things that come to mind.
Off the top of their headS because they are plural. Multiple people have more than one head...
Off the top of my head, I believe that I can.
Off the top of my head: warden
Off the top of my head: kid who fell
9.9 off the top of my head
On the top, above his head.
On the top of the head. (Anywhere else it would fall off).
0.026 off the top of my head, but do Google that!
Off the top of my head, 'absorb' comes to mind...
Chop it all off!!!