Python Multiplication with 2 decimal number as product result

Question

Is there a way to this simple equation? I'm getting as a product result : 858.2999999999999682365192655

the simple equation is this:

from decimal import Decimal

 x = Decimal(57220) * Decimal(0.03)
 y = x / Decimal(2)
 print(y)

The expected answer should be 858.30 Also tried this but it rounds this off to 858.00

  x = Decimal(57220) * Decimal(0.03)
  y = x / Decimal(2)
  z = round(y, 2)
  print(z)

I'm really sorry I'm just a beginner here in python

BTW I'm using 3.6 version of python

Edited : I'm sorry it should be 57220 :(

On a calculator, the result comes to 858. How did you get 858.30? — Shiva, Dec 06 '19 at 04:45
If you want the full accuracy of `Decimal`, you must make sure that no values are even momentarily floats - `Decimal(0.03)` is not exactly 0.03, because there is no float with that exact value. You should write that as `Decimal("0.03")`, so that Decimal can perform an exact conversion. — jasonharper, Dec 06 '19 at 04:54
@jasonharper you should add that as an answer. It actually answers the question — user1558604, Dec 06 '19 at 04:57

CypherX · Answer 1 · 2019-12-06T05:01:27.540

0

I think what you get as a result makes sense and is not wrong.

57220 * 0.03 / 2 = (572.20 * 3) / 2 = 286.10 * 3 = 858.30

So, the answer you get from the following block of code makes sense as is supposed to be 858.30.

from decimal import Decimal

x = Decimal(57200) * Decimal(0.03)
y = x / Decimal(2)
# if you want to keep two places after the decimal
y = round(y,2)
print(y)

Output:

858.30

EDIT: Updated solution based on OP's feedback about a typo in the question.

edited Dec 06 '19 at 05:01

answered Dec 06 '19 at 04:49

CypherX

7,019
3
25
37

I'm Sorry it should be 57220 :( – OMS Dec 06 '19 at 04:52
Ok. Solution's updated now to reflect it. – CypherX Dec 06 '19 at 05:01

score 0 · Answer 2 · answered Dec 06 '19 at 04:59

0

You don't need Decimal. neither you have to convert to float. Make it simple and it will give exact answer. Thanks!!

x = 57220 * 0.03
y = x / 2
print(y)

Output:

858.3

answered Dec 06 '19 at 04:59

Sapan Zaveri

490
7
18

Correct. Although i need to compare 2 values which need 2 decimal points (comparing money with 2 decimal) although thats a different story – OMS Dec 06 '19 at 05:02

Python Multiplication with 2 decimal number as product result

2 Answers2