Hmm
"I read Thorp's "Beat the dealer" and I couldn't understand how to count the non-tens. How does it work?"
At the risk of sounding somewhat condescending, there are two groups of cards: those that are tens and those that aren't. In any single deck, there are 16 of the former and 36 of the latter. The ratio of non-tens to tens is 36:16 or 2.25 to 1.
Thorp's tens-count is antiquated and no one uses it to play blackjack anymore. So, don't do any more work with it, and move on to a point-count system, like Hi-Lo, or K-O, if you intend to learn to count cards.
Don