This reminds me of a George Gamow's story (which can be an urban legend attributed to him) in Soviet Russia, I think when he was trying to flee. Allegedly, he w

This reminds me of a George Gamow's story (which can be an urban legend attributed to him) in Soviet Russia, I think when he was trying to flee. Allegedly, he was detained by some local warrior group in Caucasus(?). The local chieftain didn't believe he was a theoretical physicist, so he asked him to derive the n-th error term of the Taylor expansion. Fortunately, he was able to do that and save his life! I take it as one of those lessons of usefulness of mathematics in daily life. :-)