Addition by subtraction

At the mid-term we began our subtraction intensive study hoping that would only take a couple of weeks to be refreshed on the concepts. I was then hoping to spend the last portion of the summer with story problems and mid-level second grade math.

Unfortunately, when we began the subtraction focus, it became evident that subtraction was a little further behind than I had expected. It’s no wonder that Sara hated school so much, when you’re trying to figure something out and the class keeps moving forward, it’s frustrating and scary. In math, if you don’t get basic addition and subtraction, you’re going to struggle with anything else math-based.

So, we start at the beginning; first grade, subtraction day 1.

I’m going to try a different approach with subtraction. We’ll start out working subtraction by numbers of 1 through 5 using points. So 10 – 3 is figured by counting down 10, 9, 8,7 using three points on the 3 to count backward (like the picture to this post). With 6-9 we’ll use a counting down method. I’m thinking that we get really good with a couple methods and have Sara practice them for speed (and accuracy) and we should be in good shape pretty quickly.

Sara is getting really comfortable with addition so I’m also trying to work number combinations like 5, 7, 12 (5+7=12, 12-5=7, 12-7-5) so she can use addition to compute her subtraction. So far, not so good but we’ll keep working on a few key combinations.

While it may seem like we are behind, I’m encouraged by Sara’s skip counting (preparing for multiplication). So far we have:

– 2’s up to 100 (goal achieved)

– 3’s up to 24 (goal achieved)

– 4’s up to 20 (goal is 32)

– 5’s up to 100 (goal achieved)

– 6’s nothing yet (goal is 42)

We can spell our numbers to fourteen (20 is the summer goal).

We had a new lesson that falls under Big Concepts for Little People; partnerships. Sara wanted a set of walkie-talkies and didn’t have enough money and I kind of wanted a pair for my up coming hunting trip. So we worked together to determine what features we wanted then went to Amazon and researched which models met our requirements and finally read customer reviews on our candidates. The one we wanted was $60 but Sara only had $6 to spend. She had an idea, a product and a little money (skin in the game) but needed a money guy to back it…aka me. So we agreed on the terms and cost-split and the partnership was formed for the walkie-talkies.

I know it seems like a lot more trouble than just saying “no” to the walkie talkies or saying that we will just buy them, but I think it’s worth it as I was able to teach a concept of a partnership (and to some extent joint-tenancy) and how to research (and sell to investors) a product. I’m sure we’ll go over this concept many times as the girls grow – cell phones, bicycles, car, etc.