Originally Posted by Love2Dolphins
... at K level (lack of exposure to certain materials, etc.)
You mentioned your child doing algebra/geometry... which has not been taught in kindergarten. Gifted kids often push for "more" in areas of interest, and parents scramble to keep up with them.

... only administrate few achievement subtests in public schools
Schools may test relative to criteria they deem important for their own gifted programs/services. This may differ considerably from other/outside programs/services. For example, DYS describes a minimum of 99.9th percentile... the extreme outliers.