Yes, I know I skipped mission 2. I don’t want to get involved in Twitter, I’m afraid it will eat up to much of my time. So on to mission 3: collaboration.
I have looked at most of the sites listed before, but today I checked out the estimation 180 again. I like the idea of building number sense in this way. I recently asked my students to give me an estimate of the population of the large town next to where the school is and the answers varied between 50,000 and 300,000. Since the actual value is around 120,000, I think they did ok.
It is not something that I’m going to incorporate in every lesson, but it is something that I want to try to do more often. It doesn’t have to be a separate activity, but even when discussing text book problems I could spend some more time on coming up with an estimate at the start.