&quot;Floating point numbers are almost always a mistake.&quot;<p>This. The problem is that it&#x27;s almost impossible to internalize this without having first-hand experience - experience which usually takes years to accumulate. By coincidence, over the last month I had to explain the problems with floating point numbers to non-technical people on two disjoint occasions, and failed miserably each time, because the technical details are too complicated and the examples too obscure. The &#x27;store account balance in double, let&#x27;s put the remainder on our own account&#x27; parable is the only example that sort of works but then they look at you blank-faced and say &#x27;we&#x27;re not a bank&#x27;.<p>Just venting I guess. It&#x27;s the simple things in mapping real-world things to bits that trip me up the most - why is it so hard to represent &#x27;numbers&#x27; in computers? Why is it so hard to represent &#x27;date&#x27; in computers? Why is it so hard to represent &#x27;locations&#x27; in computers?