Programming · Flashcard
Why does 0.1 + 0.2 == 0.3 evaluate to False?
- ABinary floats can't represent those decimals exactly — tiny rounding errors remain
- BPython compares floats by identity — equal values still live in distinct objects
- CThe literals parse as strings first — arithmetic concatenates before converting
- DAddition promotes the result to double precision — the comparison spans two types
Why this is the answer
0.1 and 0.2 have no exact binary representation, so the sum is 0.30000000000000004. == on floats compares values (not identity), the literals are numbers from the start, and Python floats are already double precision — there's no mixed-type promotion.
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