When I started teaching, estimating was frequently done; maybe weekly to help build number sense. As standards and time have changed, it seems the love classroom teachers and students once had for estimation has faded. I don't think I realized how much it had faded until today during my mini lesson.
I was measuring a crayon box to demonstrate how you can use a physical unit, a centimeter cube and use multiple copies of the physical unit to find the length. I placed random spaces between the centimeter cubes and we discussed right away how the gaps of space weren't supposed to be there. I was then able to introduce measuring by starting at the endpoint/beginning of an object. As I switched to measuring the width of the crayon box, I asked my students to make an estimation about the crayon box width.
Several students asked me what the word estimation meant. I saw several faces with a puzzled look. My student's expressions showed a look of questioning and wanting to understand more. I then made a connection to our work in reading and their looks of puzzlement went away. Estimating is like predicting as readers. It's so important we take the time to make connections between subject areas/disciplines.