Reddit mentions of Spectrum | Math Workbook | 3rd Grade, 160pgs

Okay my friend, I happen to love Amazon. First - http://www.corestandards.org/read-the-standards/ That will give you a firm resource to start with. Then I have used some Spectrum Products that have been relatively straight forward. https://www.amazon.com/Spectrum-Math-Workbook-Grade-3/dp/1483808718/ref=sr_1_2?ie=UTF8&qid=1467990139&sr=8-2&keywords=spectrum+math ..... https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=spectrum+workbooks&rh=i%3Aaps%2Ck%3Aspectrum+workbooks .... Then I have used some Kumon workbooks.... https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=kumon+workbooks&rh=i%3Aaps%2Ck%3Akumon+workbooks.

I would consider (if you are able) keeping him at home and not sending him back to school. BY ALL MEANS DO WHAT IS BEST FOR YOUR FAMILY. but... Kidos that are high functioning autistic and have ADHD - are usually highly gifted and can go through school subjects and grades rather quickly. I home school year around. Routine is paramount - (my kiddo is in the same boat as yours - high functioning autistic and adhd and she is highly gifted) She goes on vacation when we go on vacation (about 3 weeks a year), she gets sick days when she needs them, holidays etc. If we were to take 3 months off in the summer I would have a heck of a time trying to get her back into a structured routine, so our "time off" is treated as out of the normal and we can quickly transition back into our regular routine.
I purchase curriculum when we need it, she completes a concept and we move forward. I do not hold her back. I have purchased workbooks and she has completed them in under a month, we move forward as long as she understands the concepts, and is able to compound on them. My daughter is 9, she is currently in the 5th grade, in most subjects. She has decided to be a marine biologist, she is studying 6th grade marine biology and is doing fantastic. She loves minecraft - she is learning to write code for minecraft mods, with python. She will not memorize math facts, and she cannot do 15 spelling words each week - her adhd wont allow it. So I do not make her do "traditional flashcards" but when she does her math, and she does not know that fact, I make her repeat it once, and she has it memorized very quickly - probably quicker than her peers with flashcards. She can spell asparagus - we do "spelling" and grammar as she is writing reports for science or free writing for english, or even hand written letters to friends. I cannot force her to do handwriting practice either - but she cannot give me a document I cannot read, without completed sentences or defined paragraphs. In addition, because she is a girl, we use glitter gel pens and study "fonts" and practice handwriting. She goes to a local dive shop and takes scuba classes. (she can be certified at 10 years old)

My real point is that kiddos that are autistic/adhd/highly gifted are incredibly easy to teach, when you find out what their "key" is.... My kiddos key is Marine biology and Minecraft. I can teach a lot of subjects through those two "topics". It is not easy... not easy at all, but it is AWESOME!

You are going to be just fine. Don't let the "system" overwhelm you and just "RUN WITH SCISSORS"!!!!