An entertaining look at floating point computation and absurdities that you might encounter if you are not careful. The video is entertaining; the details are in the article.
Computers were originally conceived as devices for performing mathematics. The earliest computers spent most of their time solving equations. Although the engineering and scientific community now forms only a miniscule part of the computing world, there is a fantastic legacy from those former times: almost all computers now feature superb hardware for performing mathematical calculations accurately and extremely quickly. Sadly, most programming languages make it difficult for programmers to take full advantage of this hardware. An even bigger problem is the lack of documentation; even for many mathematical programmers, aspects of floating-point arithmetic remain shrouded in mystery.