I'm confused what you mean by the query of adding 55 + 66. I asked 5.6 Sol on Medium (but pretty sure any model would work at any level) this query:

"Can you add 55 to 66 and explain how you reached that output result"

And received this answer:

"55 + 66 = 121.

Add the tens: 50 + 60 = 110. Add the ones: 5 + 6 = 11. Combine them: 110 + 11 = 121."

Do you mean something else? Do humans do something better than this?