for teachers:
Just because a kid can't/won't show their work or explain their work for math doesn't mean they don't understand the concept. The students that do everything in their head are probably your most gifted students, even if they make careless errors in the process.
If a child wants to read an advanced book and is enjoying the book, let them. Don't hold them back to an arbitrary standard/level that some "literacy expert" has decided is appropriate for that age or grade level.
Recognize that a gifted child may be very advanced in some subjects but not others. Teach them at an appropriate level for each subject.
If a student earns a very high score on a standardized reading or math achievement test, accept the score. Don't argue that they must not really understand those concepts, be at that level, or maybe they are just good at guessing. If a test has proven to not be valid/reliable, stop wasting everyone's time with the test.
If a parent tells you their child needs more advanced work,don't assume that the parent is over-estimating the abilities of their child or "pushing" the child to perform above their cognitive ability. If a child is incapable of understanding/learning the material, then they wouldn't be performing at an advanced level. Children should be given material that makes them progress and continue to learn, even if it is beyond what is expected for their age.
The goal of school should be to teach every child. Not have every child gain a certain level of mastery as defined by the state or federal government, or the school district. Creative strategies need to be employed to ensure that each child is making progress. Do not attempt to fit the square pegs into the round holes.