Okay, raise your hand if you're an elementary teacher and just the mention of the distributive property makes you break out in a cold sweat. Go ahead...no one can see you. Hmmmm, that's what I thought. :)
The common core standards are all about the properties, and that's very new to most elementary teachers. It's okay to admit that you had to go back and brush up on "big" math. Last week I got an email from Terry, a reader in New Jersey. Before I get into her request, I want to let you know that Terry is the director of a wonderful organization, Free Military Child Tutoring. Be sure to check out her website! So, Terry was working with her third graders on the distributive property, and she wanted some activities that would help her kiddos develop a deep understanding of the distributive property.
CCSSM 3.OA.5 reads, in part: Knowing that 8 x 5 = 40 and 8 x 2 = 16, one can find 8 x 7 as 8 x (5 + 2) = (8 x 5) + (8 x 2) = 40 + 16 = 56. Whew! That's a mouthful! To put it in elementary terms, you split 7 (one of the factors) into 5 + 2 (friendlier numbers), multiply 8 x 5 and 8 x 2, and add the products together. Not so bad, really. Now I don't know about you, but 8 x 7 was a hard fact for me, and maybe this strategy might have helped!
As with any other math concept, it's important to take this skill through the concrete (manipulatives) and representational (drawing) stages before the abstract (purely symbolic) stage.
Next, I have a little game that students can play to practice representing arrays and connecting them to equations.