This inspired me! I am all about implementing a low input <=> HIGH OUTPUT product into my class. So, I started. Each day I would start class with an image on the projector with the daily estimation problem. Kids would come in and know they had a minute to write down their guess before I showed them the result. (BTW: I am Type A, so they have a document to fill in!)
I also wanted them to analyze their guess. After each answer I had them write a +/- number to show how above/below their estimate was to the actual answer. Finally, after 20 days of estimating, I would have them average their +/- numbers to get their average 'error'. My highest student error was in the 1,000's and my lowest was 0.4.
Now, I have not yet had kids translate this estimation into their regular daily lessons, but I believe it will happen. Like anything it is a process. Slow and steady wins the race!
Finally, I saw a post on Twitter about a calculator that won't give you the actual answer until you type in your best estimate. This nearly floored me. Talk about having the best of both worlds: using a calculator to speed up your work, but also THINKING while using a calculator!