I think was a stand out at the Potts School. I mean he could not fit into that Potts uniform with all the 7th graders at the school. Besides Mr. Drysdale held the mortgage to the school. Now lets see, Jethro was able to do goozuntas & knots when calculating math! I think Jethro should have carried out being a brain surgeon, that boy was a genius! Well-Dogey!

His way of viewing things made for a lot of interesting episodes

The more Jethro thought he knew,the more it turned out he needed to learn.And let's remember that Jethro might have had a little more book-learnin',but his lack of wisdom still made him seem like a dope.

I just thoughtnof something else about Jethro's education.When they first got to Beverly Hills,Jed told Miss Hathaway that Jethro had gone to school in Oxford.Miss Hathaway didn't know how backwoods they were- and didn't know about the Oxford elementary school in Bugtussle-built by the river where the ox would ford.

Miss Hathaway:I assume when he was younger,he went to Eaton!
Jed:Jethro went to eatin' the day he was born.

I thought Jethro made up for his lack of
smarts with a lot of imagination....Who else
would come up with the idea of a 5 second
car wash by dunking the truck in the cement
pond? And the double-knot spy was the best
of the best....especially the iron hat....
Jethro may not be smart, but he is very, very
creative....Who knows, maybe one of his hair
brain schemes could cure the common cold (just like Granny's "cold cure")

The more Jethro thought he knew,the more it turned out he needed to learn.And let's remember that Jethro might have had a little more book-learnin',but his lack of wisdom still made him seem like a dope.
I don't really think it would have helped.