Wow. that is great, but a lot to decide on your own. I think given how helpful the school is, I would ask them to partner with you in determining your son's level of placement.

A bunch of thoughts come to mind:

1. when is this supposed to happen - immediately?

2. Are you looking at subject acceleration or grade or a combination of both (skip 5th and additional acceleration in one or two subjects?). My DS was adamant that he not be grade skipped, although I can see situations where I would not let the child dictate the result.

3. What achievement scores do you have for him. By his age, I don't think IQ would be what I would be looking at for determining placements, at least in isolation.

4. Math should not be that hard to figure out. Work with the district and ask them to give him the end of year 6th grade test, 7th etc. until you get to where he no longer knows the material. Math builds upon earlier concepts. If a kid doesn't know how to multiply and divide fractions and decimals, it is going to be awfully hard to learn alegbra (you can fill in some gaps, but if he only knows 50% of the 6th grade material I would probably not put him in 7th grade math). I would likely correlate the science to the math, perhaps with a provision for some special projects, a science mentor or something along those line (this in part because often upper level science requires math knowledge).

5. Is there a curriculum specialist you could meet with re: the reading/writing curriculum. I would start there. If not, I would review the curriculum and see what it says and where is a good fit. Remember, you could do 2 years and see how it works, and then do another year up if you need to - this can be incremental. How are his writing skills and concentration, etc. For example, my DS loves to read and consumes adult non-fiction regularly, but if he had to write a 5 page report it would probably not be 4 years above his level (maybe 2, but prob. not 4). He understands the concepts and has the knowledge, but has not yet developed the skills to communicate well in writing. Once again, you have to think about the demands in terms of homework, tests, etc. I would guess that a social science placement could mirror the LA placement (a simple proxy, so maybe one that others will have more insight into).

Remember, once you do one thing, it isn't set in stone. Baby steps are fine. And at some point, if you sub. acc. in all subjects, it seems like the school would likely just want to grade acc. him.

let us know more, Cat