the.com/nan

The number that means 'I tried math and math said no.'

means NaN is the floating-point value meaning 'this is not a valid number,' produced when an operation like 0/0 or an invalid square root has no sensible numeric result.

from Straight from computing, not classical word-roots: NaN is an acronym for 'Not a Number,' formalized in the IEEE 754 standard for floating-point arithmetic (first published in 1985). Engineers needed a way for a calculation to fail gracefully instead of crashing the program, so they built a special reserved bit-pattern meaning 'this slot held a number, but the math broke it.' Its spread into pop-culture meme status comes from programmers encountering it unexpectedly in spreadsheets and code — the digital shrug of 'don't ask.'

stands for
Not a Number, programming's shrug emoji
weird property
NaN never equals NaN, not even itself
common cause
dividing zero by zero, or bad data
also means
delicious flatbread, unrelated and better
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