Theory:

     “A man isn’t smart enough.”
 
     “Sure one is.
 
     Margie wasn’t prepared to dispute that. She said, “I wouldn’t want a strange man in my house to teach me.”
 
     Tommy screamed with laughter. “You don’t know much, Margie. The teachers didn’t live in the house. They had a special building and all the kids went there.”
 
     “And all the kids learned the same thing?”
 
     “Sure, if they were the same age.”
Explanation:
  
Margie said that a man teacher is not as clever as the machine teacher. Tommy tells Margie not to estimate the human teacher as too low.
  
Margie did not want to argue about it and said that she did not want an unfamiliar man, the human to come home to teach her. Tommy felt it was a joke whatever Margie said.
  
He said that teachers didn’t go to the students’ house to teach them instead they had a special building; a school and the children went to the school.
  
Margie was surprised and asked that did all the children learn the same thing.
  
Tommy said yes, all the children studied the same thing if they were of the same age.
  
Meanings of difficult words:
 
Numbers
Word
Meaning
1.
Betcha (informal)
(I) bet you (in fast speech): I'm sure.
2.
Dispute
Disagree with when you are opposing something.
Reference:
State Council of Educational Research and Training (2018). Term-1 English Standard-9. The fun they had - Isaac Asimov (pp. 150-153). Published by the Tamil Nadu Textbook and Educational Services Corporation.