Square Roots by Hand

A little while back, several of my fellow math-and-science bloggers and I got into a discussion of a particularly hare-brained way to reform math education, and I mentioned that nobody in my generation seems to have learned how to take square roots by hand, or at least, not within any formal school curriculum. The comments I received suggest that cheap calculators made this phase out of the grade-school math classes by the early 1980s, or thereabouts. Today, I found that 360 has written a nice post explaining a geometrical interpretation of an algorithm for doing so.

Of course, there’s no way such a lesson would be allowed anywhere near an elementary school, because it emphasizes understanding why a method works.