Python: Difference when passing a number or a string to decimal.Decimal

Python's Decimal behaviour

# Scenario ONE
price = Decimal(33.000) # <-- passed in a number
factor = Decimal(0.3020)
price = price / factor
price = price * factor
price.quantize(Decimal("0.01"), rounding=ROUND_UP) # --> 33

# Scenario TWO
price = Decimal('33.000') # <-- passed in a string
factor = Decimal('0.3020')
price = price / factor
price = price * factor
price.quantize(Decimal("0.01"), rounding=ROUND_UP) # --> 33.01

actually the few first bullet points there answer your question https://docs.python.org/2.7/library/decimal.html