4.5 breaking apart to subtract

The strategy that we're working on today is called breaking apart to subtract and it's based on the idea that there are many ways to do a problem. So if we take a look at the first problem, it says 13 -5. So for step one, the first thing we're going to do is we're going to look at how many we're starting with. We're starting with 13. And before we take the 5 away, we're going to get rid of all the ones from the second ten frame. So we're actually going to start step one is taking away any circles that are in the ten frame. So we took away three first. Now, when we get to step two, there are already taken away for us. So it's kind of like we're erasing them. The next thing that we're going to do is we're not finished because we're not just taking three away. We're taking 5. So since we've already taken three away here, we're going to take the remaining ones from this ten frame, so we have three, take four away, take 5 away. So now from this tens frame we've taken two away. Now, now we've made we can do 13 minus three, which will give us a difference of ten, but again, I'm not finished because I still have to work with that too, and now I bring my two down here and ten minus two will give me eight. I can either count one, two, three, four, 5, 6, 7, 8, or I might just now, the ten minus two is 8. Therefore, 13 -5 is also 8.