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>Many people think floating point numbers are magically precise.

Even worse, it kicks in earlier than one might naively think. People are often surprised to hear a value as simple as 0.1 has no matching floating point representation.

(For those interested, http://www.exploringbinary.com/why-0-point-1-does-not-exist-... has a nicely illustrated explanation.)

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Being unable to represent 0.1 exactly is unrelated to any precision limitation. It's because the quantization of binary and decimal is different.

This isn't true with e.g. decimal64.

Those sorts of numbers aren't floating point, they're typically fixed point.

No, that's explicitly a floating point format. It's one of the representations in IEE-754-2008. The three decimal floating point formats are decimal32, decimal64, and decimal128. That people often use them where fixed-point math would work doesn't mean they're not floating point formats.

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