Why 0.1 + 0.2 isn't 0.3: flip the 64 bits a computer uses for decimals
30seconds
Type 0.1 + 0.2 into almost any programming language and you get 0.30000000000000004. Nothing is broken. Computers count in powers of two, and a tenth is an endless repeating fraction in binary, so it has to be rounded to fit in 64 bits.
Flip the real bits of a double yourself and see the exact value they stand for, and learn how a rounding error this small helped cause a deadly missile failure in 1991.
Deep dive · 3 min
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