[aaaronic]

Sure, but .1 is definitely representable, so they can be excused for finding it a little unreasonable that .1+.1+.1+.1+.1+.1+.1+.1+.1+.1 doesn't equal 1 in many languages.

Explaining _why_ .1 isn't representable requires explaining IEEE-754 and explaining _that_ requires an understanding of binary numeric representation.

I teach college students who find this confusing, so I think it's fair that the average person finds floating point behavior confusing (in fact, I've had to explain to Physics Professors doing computation simulation work why their 1-<tiny number> isn't working out the way they expect -- though they initially tried using double doubles to get around the problem).