Hi Veronica
Conceptually what you have is similar to the following:
(1/3)+(1/3)=(2/3)
This is conceptually easy to write on a piece of paper in fraction form but
in decimal (base10) form you need to write it out as an infinitely long
series of numbers to store it precisely (which you cannot do):
1/3=0.3333333...
In decimal you have 10 bits which we associate with the following
characters to store a number (0,1,2,3,4,5,6,7,8,9).
You essentially have the same issue with your code. Just to simply it
typing in:
0.4+0.2
Also gives the same result:
0.6000000000000001
In binary you only have 2 bits or if you rather only 2 characters to store
a number (0,1). Numbers in a computer that are stored in binary (base 2)
have the same issue as 1/3 in decimal in that it cannot be precisely stored
and must be rounded at the end. Like the length of a piece of paper for
writing down a number, the memory that a computer has to store a number is
finite.
Binary notation can be thought of as converting a number to decimal form
using scientific notation but with only 2 characters opposed to 10.
For more details about the underlying principles of this problem look up
float16 and the classical example 0.1.
The binary representation of 0.1 is recurring:
0.1 (base 10) = 0.000110011001100110011... (base 2)
To address this in your code, use the round function to round your value.
For example:
round((0.2+0.4),2)=0.6
Will round to 2 decimal places.
round((0.2+0.4),16)=0.6000000000000001
Will round to 16 decimal places giving you the same value as before.
Philip
On Sunday, March 8, 2020 at 8:26:50 PM UTC, SarahC5 GoRonix wrote:
>
> Hi, my name is *Veronica*, I am new to Python programming.
> I am using Spyder, and here is what is in my code. It's giving
> me the *wrong output:*
>
> *EDITOR___*
> num1 = input("Enter a number: ")
> num2 = input("Enter another number: ")
> result = float(num1) + float(num2)
>
> print(result)
>
> *CONSOLE_____________*
> Enter a number: 4.4
>
> Enter another number: 2.2
> 6.6000000000000005
>
> *QUESTION________________*
> Why is this the output? It's supposed to be 6.6
> Why is it adding those zeros and the five at the end?
>
>
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