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Wednesday, January 30, 2013

Teaching Partial Product Multiplication

Partial Product Sample
I balked when I was first asked to teach partial product multiplication.  "This is crazy," I remarked, "It takes up so much space, and it's such a lengthy process."  But after teaching this method, I realized how terrific the process is both for solidification of place value understanding and mental math.

Partial product is part of the new standards for math too.  Yesterday, I dove right into teaching that algorithm, and as usual, once I got a feel for how students reacted to the process, I needed to go home and rethink the lessons to come for this group.  Every group of students reacts to teaching points in different ways, hence the need for responsive, tailored lessons.

Here's how the teaching will roll out over the next couple of weeks:

1. First, we'll review the area model for multiplication.

2. Next we'll review partial product with models and story problems.

3. After that students will practice a lot.  They'll have access to this great partial product film and the practice pages and more films on our class math website.

4. Later, for those that are ready, we'll introduce the traditional algorithm and perhaps others.  Surely in fifth grade the traditional algorithm will be taught.

Stepping students into multiplication via partial products builds facility and fluency for understanding and computation.

Partial Product Organizer for 2 X 2 Problems (Expected 4th Grade Standard)