Growing up, when thinking about the term estimation I thought, "what's the point?" I mean we spent years and years figuring out how to get the exact answers to problems and now we are required to learn estimation skills, which is just close to the right answer! I would also wonder why we don't just use estimation skills for everything instead of doing all the work to find the right answer. My thoughts have changed since then. :)
As I think about everything that I do during the day that relates to estimation, the list is long! I woke up looked out the window and thought to myself its probably 8:00 am so I should probably wake up. By the way it was 7:52 am. I then started making my shake for breakfast which needed a tablespoon of cocoa and a teaspoon of lemon juice. I don't know about you but I hate dirtying dishes when I don't have to, so I just ESTIMATED. By the way I don't know how close I was to the right amount but it did taste good. I am also decorating my house and need to go to the store today and buy two shelves, both about six feet, then I thought to myself, I better measure before hand or it will look dumb. But before I get those shelves I need to make sure that they will fit on the wall above my bed and end tables. That is where my theory of "what's the point" comes along. Although estimation may be easier to do, its not always going to work. A lot of times we need the EXACT answer. My list could go on an on about everything that I have estimated today.
So now the question is how do you teach estimation? I really don't think that their is any perfect way to teach estimation. I mean growing up I don't recall any certain method to estimate. I do remember estimating length though. I feel like that was the first for me was learning from measurements. I work with a student at the school I work at with his estimation skills as well. I was told to first work with him on measurement. I see that as a benefit for two key reasons. Number one measurement is a huge part of our everyday lives, at least that's what I think. Number two is measurement is very much visualization. I know what a ruler looks like, which leads to me KNOWING about what an estimate is for a foot. I know that my thumb is about an inch. Little ideas like these stick in your brain and help you with estimation. Other ideas help as well, like when the sun is straight above you, it is probably around Noon. While reading and article called, "Estimation," by Robert J. Doman Jr. I could understand how you should start teaching a student estimation with adding and subtraction through rounding. That is a probably the best way I could estimate. On the other hand he gave an example of 298 + 403. Saying that 298 is 2 less than 300 and 403 is three more than 400, so you should be able to estimate knowing that information. Students can certainly do that but I feel like that is way to many steps.
When I am a teacher I hope to make estimation fun for all the students. maybe have a candy jar filled with something and they must estimate the number in the jar. Or even estimate the length of something without measuring. I also found this website that I found pretty fun. I played an estimation game with multiplication, and I did horrible. I can not estimate very fast. If I did it enough I think I would be great at it. I will definitely be using this site in the classroom.