One skill that I've found to be especially useful in investment and business -- often because others are so bad at it -- is to make good determinations on the value of any given thing (i.e., what others will pay for that thing).<p>Being able to find and take into account available data and, in the context/absence of such data, make a best guess based on "intuition" has been highly valuable in everything from freelance contracting to negotiating salary and equity to determining pricing for our startup's products.<p>Now that I have a child, I find myself a bit surprised that there isn't more literature out there on how to teach/develop this skill for children. Does anybody have good resources or experiences to share on teaching children to reason through determining the value of concrete and abstract things?