Developing rational patterns of thought in children is very important and I'm glad Gunnar brought that issue up.
I wanted to share with you some thoughts I have regarding estimation games.
From an early age I've been constantly calculating various kinds of estimates - e.g. "how many people live in this building", "how long will it take to cross the US on foot", "what's the height of that tower", "how many BMWs are manufactured annually" and so on.
I believe that practising this technique is not only fun but also helpful. Sometimes one has no way or time to acquire accurate information regarding something and even a rough estimate can be very valuable.
People are often surprised when they see me do it whereas for me it is completely natural. I think the reason is that I do it from a very early age.
I think it's easy and natural for children to grasp if this method is introduced through everyday experiences. By making this into a game children can gain intuitive understanding of quantitative techniques. I suspect many children can enjoy this kind of games.
I'd like to hear your thoughts on the subject.
Do you remember yourself doing something like this? From what age? Do you practice anything similar with your children?