Adding 2-digit numbers - followup

So today I experimented, and gave my daughter a problem 15 + 25 for starters, to see what she'd do.

1 5
+ 2 5

3 10

She promptly wrote down 3 and 10. Then she looked at the numbers, kind of wondering, saying "It's ten three." I asked her how would we say the number, pointing with my finger and making a sweeping motion from 3 towards 10, and then she said, "Thirty-ten."

I said yes, it's thirty-ten, but we say it differently normally. Then I asked her to find it out using abacus. She easily found it was 40. Then we erased her numbers and wrote in 40.

She did two more similar problems on her own, first adding tens, then ones (as her custom seems to be), and then erasing the numbers and changing them to the right result. She seemed very happy for being able to understand the gimmick.

So we did all that without discussing 'carrying' or putting little number 1 up on top, or anything.

I figure next time I'll try a problem where the ones add up to 11 or 12.