11032012, 07:31 AM


I recently taught 2 digit by 2 digit multiplication and really focused on decomposing the second number....I believe this is the partial products concept. I taught it using our math interactive notebooks, so it wasn't a really exciting lesson but it was really effective. I've never had the kids pick up on the concept so quickly! For example: with 25X32, have them write 2 multiplication problems with 25 as the top number. Then, have them decompose the second number...30 and 2. The key is that when they're multiplying 25 by 30, have them move the "0"over one place to the right so they're really just multiplying 25 by 3 and then just adding the "0" on the right. Then, have the multiply 25 by 2 and finally have them add the two products. Teaching them to move that "0" to the right and then add it at the end enabled almost all of my students to now be able to multiply 2 by 2 digits.
