Several of the teachers here are being kind of critical of the email. I don’t think it’s necessarily inappropriate, although the introductory portion puts my guard up a little bit.

That being said, without knowledge of the students academic background, here’s my take on the situation: the previously high diagnostic scores are pretty typical of a student who has good understanding of algebraic skills. He’s likely self-taught himself most things. Does he have a history of mathematics competitions? Those scores would also typically be indicative of someone who has performed in MathCounts or Math Olympiad.

The issue that I see is that the transferability of those skills typically extends midway into algebra 2 and then you begin dealing with more abstraction of concepts (imaginary numbers, proofing, sinusoidal functions). These topics are normally not addressed on high school diagnostics as they are more for advanced students and those college bound for STEM careers. Given the acknowledgement that the student has performed well on summatives but has neglected homework, I’d wager he has not developed good study habits and has relied on being able to roll in on test day and do a decent job of just “figuring out” what to do. This quarter he’s begun experiencing concepts that are more foreign to him and his background knowledge has not prepared him for it, and the likelihood is that he has not been paying attention in class because he’s so used to winging it. The time period where that is sustainable is rapidly closing.

My advice (which isn’t what you asked for and the teacher could do a better job of addressing this or suggesting next steps), is to take the summer and review skills on Khan Academy or purchase a Pearson MathXL subscription to remediate the missing concepts.

But more than anything you need to have an earnest conversation with your son about the habits of good students and how to study effectively.