I agree, I agree, I agree! BUT, I really need to teach the algorhythm for multiplication as my students will not have the advantage of Investigations in sixth grade and will be EXPECTED to already know the algorhythm. It was introduced to them during fourth grade, but they do not seem to remember how to do it without me specifically teaching it. I have avoided teaching it so far, since I wanted them to experience what it was like to "cluster" multiplication and division. I am hoping they will be able to hold onto this strategy to use later in algebra.
I did not teach the algorhythm concurrently with clustering because I really thought they would get confused (I have a low-ability class for the most part), and I wanted them to experience the power of clustering. They are so excited about math right now and even my lowest student thinks of herself as a math whiz!
Now I am faced with the task of deciding whether to pull out the Silver Burdett for awhile to teach their multiplication unit, or design my own mini-unit. I want to use "Building upon Numbers You Know," but am unsure if I can teach both to mastery level at the same time. Please advise me on how others are juggling this!