Hi, Cricket3.
3rd edition just came out last year, so your school would've used an earlier edition. My understanding is that they're pretty similar. 3rd edition has a lot more digital content, though, and there were a few other changes.
That was exactly the kind of information I was looking for, though. And it sounds like your experience was very similar to ours. He's had more than one challenge problem per unit but not by many.
Thanks so much for your feedback! I know that one response isn't much of a sample set, but your experience reinforces my belief that this is just how Investigations is run. And that I'm in for a fight getting my kid math instruction that's at his level. :P
Thanks!
echofuzz
