This post feels particularly applicable since I just came across a huge bug in ruby's BigDecimal package.

If you use ruby 2.1, be sure to upgrade to BigDecimal 1.2.4.

https://www.ruby-forum.com/topic/4419577#1133001

The bug is basically: if the divisor is less than 1, the result will be 0.0.

https://gist.github.com/donpdonp/c36b33b861cea49c0a86