Do you know what math curriculum the school uses? I ask because our school uses Everyday Mathematics. The plan behind this curriculum is a spiraling sequence. Meaning, they hit the same topics each year, just in greater depth and complexity each year. So, if you enrich a K curriculum, you basically get the 1st or 2nd or 3rd grade curriculum, depending on the level of enrichment. This could be a good thing in that she will essentially be accelerated through the curriculum. But this could be a bad thing in that she will essentially be accelerated through the curriculum. It could meet her needs, but it could also compound the problem of her being beyond the curriculum and force her to sit through even more repetitive material as she advances through the grades. If every teacher she has is willing to "enrich" her and move her through the curriculum at her pace, then it could work. I'd be a little concerned that she's only getting math instruction at her level once a week, although it will be a nice opportunity for that teacher to see how quickly she progresses and at what level, exactly, she needs to be taught. Are they open to discussing an acceleration for next year to address her needs, in case next year's teacher is unable or unwilling to continue to "enrich"?
