[reinsley]

Gents,

I started a test epub. I did not imagine the structure it would take.
Obviously, with your experience, you anticipate all the sensitive points.

For the page break, I will probably use :

Into stylessheet.css :
.WordSection {
display: block;
page: WordSection1
}

or </br>, I will see.

For the score I could write a reminder of the questions total number in the theme or section. As the reader comes back to the sub-section as long he is wrong, he can see the progression, question4... question5...question6 out of ten. And a kind of progress bar with stars or something.
And a note could send some kind of popup message. It's still abstract for now, the simplier will decide.
WRONG leads again to the start of the question, CORRECT leads to the next question. And a link to go to the next sub-section as the reader could be trapped without exit.

I don't know if I can post into the forum my skeleton epub, in case anybody would like to comment...

I keep your precious advices about Export as HTML and also Sigil tools.
I use plugin Sigil to make links.

Best regards