Can someone explain this: 0.2 + 0.1 = 0.30000000000000004?
math, python, python-3.x
Solution
That's because `.1` cannot be represented exactly in a binary floating point representation. If you try
>>> .1
Python will respond with `.1` because it only prints up to a certain precision, but there's already a small round-off error. The same happens with `.3`, but when you issue
>>> .2 + .1
0.30000000000000004
then the round-off errors in `.2` and `.1` accumulate. Also note:
>>> .2 + .1 == .3
False
Problem
Duplicates: How is floating point stored? When does it matter? Is floating point math broken? Why does the following occur in the Python Interpreter? ``` >>> 0.1+0.1+0.1-0.3 5.551115123125783e-17 >>> 0.1+0.1 0.2 >>> 0.2+0.1 0.30000000000000004 >>> 0.3-0.3 0.0 >>> 0.2+0.1 0.30000000000000004 >>> ``` Why doesn't `0.2 + 0.1 = 0.3`?