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how come 2-√2×√2 is not zero, is all programming wrong?

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 ## Why 2-√2×√2 ≠ 0 in Python: A Tale of Floating-Point Frustration 


Have you ever coded in Python and gotten a surprising result?   Let's say you try this:


```python

x=2

result = x - (2**.5) * (2**.5)

print(result)

 


You might expect the answer to be zero, since 2**(1/2) times itself is 2 , and 2 minus itself is zero, right? ➖  But hold on!  Python might print something like:


```

0.0000000000000004

```


What's going on here?    The culprit is something called **floating-point arithmetic**.  Computers store numbers in a special way, kind of like having a limited number of decimal places for everything.    This means super precise numbers like the square root of 2 can't be stored perfectly.  


In this case, that tiny imperfection in storing √2 gets carried over when we subtract it from 2.  The result is a small, non-zero value.    It's like trying to perfectly measure ingredients with a teaspoon – there's always a little leftover! 


**Key points to remember:** 


* Floating-point math is super useful, but it's not perfect for ultra-precise calculations.

* Not all calculations will equal exactly what you expect.

* For super precise work, there are special Python libraries designed for high-accuracy math. 


So next time you see a surprising result in Python, remember the floating-point gremlins might be at play!  Just a sprinkle of awareness can help you understand what's going on behind the scenes. 


Interactive example:


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