Multiplication result is negative zero

Question

can someone tell me why the output of the code mentioned below is negative zero?

a * b = -0

here 'a' is of type long, b is an object of the decimal class ..... and if a = -28 and b = 0, then the output is -0

Answer 1

From Python decimaldocs:

Signed zeros can calculations that are not valid. They keep a sign that would lead if the calculation were performed with greater accuracy. Since their value is zero, both positive and negative zeros are considered equal and their sign is informative.

Answer 2

It explains everything:

http://effbot.org/pyfaq/why-are-floating-point-calculations-so-inaccurate.htm

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