I've taught Investigations for two years (grade 3) and I always struggle with how to assess students' work that involves writing. Sometimes they are very clear about explaining their steps and why they did them, but their reasoning or calculations are wrong. Other times their explaining is lousy but I can figure out what they did and it works and is accurate.
How are other people grading this kind of work? Do I give separate grades for explaining vs. efficient strategy and accuracy?
What about the kid who has writing difficulties? Do I continually penalize him when his mathematics might be good?
I would appreciate hearing what others have done with this issue.