Kristin,
We do drill math facts, but with a twist. I have a workbook of math drills. I copy the pages and we make a competition out of it. DS LOVES to beat DH and I on them. We handicap ourselves by having to do it with our offhand or with the page upside down. We do not make it easy for him to win, but he is getting about as fast as us on the addition and subtraction. Multiplication and division are still weighted toward Mom and Dad. He also really likes to beat his personal best times so we do the math drill, then chart his times on a graph so he can see how he is doing. (and lay the groundwork for stats...) (edit, since we crossed posts..DS is in third grade lol)Aleks online math program has really helped DS to learn to stay focused and double check his work unless he wants to do extra drill. Those piepieces really get his attention.
Our WM issue is more to do with the physical act of writing while composing. So much of his school activities require him to write x number of sentences in cursive or write a 2 page journal entry about his weekend. That sort of stuff. DS literally cannot keep up with how to form the letters, spell the words and write coherently all at the same time. He also hates to spend more time than he thinks he should on the assignment. We are working on his keyboarding skills to let him type a rough draft before physically writing it. Much easier to make corrections in Word than in his notebook. We are working on brainstoming options and the use of key words to help stay organized.
We also recently started him in drum lessons (he wanted them and I'd put him off with piano for 2 years). A side effect is that the drum set requires him to focus on multiple actions at once in a way that he finds fun. I'll have to see if over time it improves other activities as well.
Not much help
I think we take the idea of building coping skills and teaching him that this will be a long term source of frustration for him and that there are things he can do to help compensate for the WM and processing issues. However, they DO require him to learn different skills from many of his classmates. Concepts that I really didn't learn until college like actually doing rough drafts lol, he is learning now.
FWIW...
