>>12713621Oh yeah, knowing how to ballpark and do back-of-envelope math is depressingly rare. It's part of a larger problem with a bunch of engineers who just plug & chug and don't actually know what they're really doing when they use that formula (or how to think in general).
Here's another fun one from a friend of mine:
>prof says to bring a calculator to the test, doesn't have to be fancy just able to do the basics>friend decides to be cheeky and bring one of those kiddie ones with the giant buttons>he encounters the square root of some gross, biggish number>his calculator can't do roots>he takes the logical course of action and uses a taylor approximation at the nearest perfect square to estimate the root>"yeah, it asked for 3 sigfigs so I took a 3rd order approximation just to be careful" 
