Without knowing exactly what's frustrating him, and how he's expressing that frustration in class, it's difficult for me to respond very specifically. However, I have a DS6 who goes to 2nd grade for Everyday Math (my DS6 is in 1st grade), and I can tell you about our experience. First though, that's fantastic that they were willing to let your DS go up two grades in EDM. It can be difficult to transition into that curriculum without getting the base "language" of EDM in 1st grade and K. Regardless of whether he knows advanced math concepts, making sense of EDM is not terribly easy when you're thrown into it in the middle.

Regarding our experience as it may be relevant to yours, my DS6 is very proud to go up a grade with the 2nd graders, but he is also more reluctant to speak up in class to provide answers, or to ask questions, because of the age difference. My DS is not low on self-confidence, although he is more of an observer, and it's surprised me a little that he's as reluctant as he is in math. Thankfully, he understands the teacher and doesn't need to ask many questions, but if he were being particularly challenged, we would have a hard time with it because he wouldn't speak up to ask questions. His writing skills are also not at a 2nd grade level, which makes it difficult for him to complete work in the classroom sometimes.

I imagine this scenario might be multiplied for your DS, since your he's going up two grades, not one. The EDM curriculum itself can also be frustrating for kids who want to move along quickly, as others have noted, because EDM is extremely repetitive, and remains so from year to year, as it's a "spiraling" curriculum, meaning they revisit the same topics in more depth each year.

I don't know if any of this is helpful, but thought I would share in case it is. I think Grinity's response is great too.

I like EDM. The reality is, we DO use multiple ways of doing math when we do it in the real world.

That said, your guy may need to be moving along faster. Take a look at compacting.

Just a quick update--- We had conferences last night and I think I know where at least part of his frustration is coming from. For one thing, they are currently learning to add with an algorithm that teaches them multiple digit addition from left to right i.e. 18+18 is written in columns and they will add the 10's, writing that answer below then they will ad the 1's place and write that answer below that.
18
+18
----
20
+16
----
30
+ 6
----
36
Not only does he not like doing the math this way but it is interfering with the way he had been doing it before so that he is now confused about which side to start on, when to carry etc... He's been able to do this problem for a long time now but got it wrong the other day because he was combining the two different methods. I think, now that I have some idea what they are doing, that I can work this out with him. We also found out that the 2nd grade class is spending 90 minutes a day on math whereas Connor's only in there for 60 minutes of it. I think he's doing quite well considering he's only getting 2/3 of the instruction time.
On a positive note, his attitude and behavior have been great. The worrying behaviors that we were seeing at the beginning of the year have disappeared or lessened dramatically since spending time in 2nd grade. He loves his science and Chinese classes, has a 'girlfriend' in Kindy and just generally likes school. Also, his reading level has gone up from around a mid 2nd grade fluency in October/November to around a mid 3rd grade level now.

Have him do a few examples using both methods side by side. Use a blue pencil for one method, a red for the other. You might also take a step back and add 18 cents to 18 cents, and track where all the pennies and dimes go. That EDM method there can be confusing if you don't fully understand why the two methods work. However, that method is a good one to know and understand because it really can make mental math easier.

Do you have a plan to coordinate with the teacher about the lost 30 minutes a day of class and teacher interaction time? It's great you got things figured out before things got dire.

So, 2nd grade teacher wasn't at conferences (just K teacher) but we went through his 2nd grade work and 2nd grade teacher had met with K teacher ahead of time to update her. She also gave us her number to call her at home.
By the time of the conferences 2nd grade teacher had basically changed her mind and decided that, while Connor's math isn't as strong as his reading, that he is appropriately placed. So, I called 2nd grade teacher and basically the discussion on her end had turned from "he's overwhelemed." to "Wow! He's doing great!" She told me that she figured out that if, instead of separating him out with the others that were having difficulty with a concept, she let him work through it on his own that almost always figured it out without any intervention. Basically, he was more frustrated over people trying to help him than by the math itself. 2nd grade teacher also said that the EM curriculum that she has been using is not school-wide but that she has used it to frame her lessons because the regular teacher didn't have a set curriculum set for her ahead of time. Knowing that, she has started letting Connor do his math in the way that works best for him.
The conversation that I expected to be a few minutes ended up lasting over a half hour with the teacher repeatedly telling me that she had, in fact, been very leery of having a Kindergartener in not only Reading, but Math as well. She was pretty apologetic and explained that she was not aware of ever having had a K child in her class that was as far advanced across the board as Connor is and therefore couldn't have imagined that it would work. I guess I can't blame her for being surprised- we are constantly surprised by him at home too. She was more surprised when I told her that neither Reading or Math is his strongest suit- that would be Science. Long story not-so-short: I think we got another convert to the idea of believing giftedness, acceleration, and accomodation

This is fabulous news!

Fantastic!

Good for you - I know that I think better when I have a chance to think aloud and be listened to, and I've seen it work time and time again. In might be true that it's not fair to ask a parent to do this sort of service for a teacher, but given how unusual our kids are, it's unsuprising.

Yippee!!! You have a happier kid!
Grinity