Concept of a "ten"

[Jason Zimba]

I was asked the following question and thought it might be productive to post it here, along with the answer I gave:
 
>During a lesson on the numbers 11-19 a kindergarten child looks at a filled ten frame drawn on the board and says that’s 10 because that’s a 10 frame and a 10 frame holds 10.
 
>Would you consider that exercising K level reasoning? Or making use of structure?
 
I replied to this with the following quick thoughts, which I’m simply pasting in here now: 
 
First, remember that the concept of a ten as a unit is a grade 1 expectation (1.NBT.2a), so the standards don’t require this kind of work with kindergarteners.
 
Not that they couldn’t work with ten-frames or get into grade 1 material early if desired, but it isn’t expected.

 As to the question itself, I think what the student’s statement might show is some measurement thinking. Effectively, she has learned the value of a conventional unit of measure (the “ten-frame”). This seems more like acculturation than mathematics. I think it isn’t possible to know, just from her words, whether she is unitizing the 10. (Which again is a grade 1 expectation.)

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