Mastering Skills

I did something in all my classes on Friday that I think I'll do periodically. Everyone got a half sheet (to turn in at the end of the period) that said basically:
What "skill" are you struggling with currently?
What did you do in class to make progress on your knowledge?
Who (besides me) did you get help from?
What specifically are you going to do this weekend to deepen your understanding?
How will you show progress to me next week?
What would you like to tell me?

Most kids worked hard (some chose to goof off, of course). I had many verbal and written comments about how this session helped. For my calculus classes, I had "reteaching" sheets written out for 3 topics (all I could come up with on my short time schedule from when I had this idea to when I implemented it). These sheets had worked out examples and then practice problems with answers on the bottom of the page.

Riddle posed by one student this week (and I'm still working on the answer), but I thought I'd share: What word is plural, but when you add an "s" to the end becomes singular?