Reflection - Learning Math Through Writing

I am really struggling with problem of how to get my kids to best learn the material I am teaching them. The day following a homework assignment is the toughest. How do I assess if they understood the homework? How do I tell if it is time to move on? These are the questions I have been faced with since the start of my career and yet I think the answer to both may have been in front of me the whole time--have them write.

Last night's homework required students to make conversions in the metric (3,000 mm = _____ m) and customary systems (108 in = _____ yd) using proportions, something entirely new to them. This is a multi-step process: set up a ratio for the unknown, set up a ratio for the base conversion, make them into a proportion, cross mulitply. It hit me that if the students can describe the process that I just described, and support it with reasoning, then they know how to do the homework. So I think I'm going to scrap the "share your answers and with a partner and choose a problem that you both struggled and we'll go over it on the board" approach. Instead, I'll have them write the process in words and go from there.