We got an issue when number is formatted asdecimal.Decimal('2E+9').

HowDecimalField counts decimals:

    sign, digittuple, exponent = value.as_tuple()    decimals = abs(exponent)

However result ofdecimal.Decimal('2E+9').as_tuple()[2] is9, which is ok, but there are no decimal places in this number.

My solution is to not doabs and instead multiply by-1.

I can prepare PR tonight if you think it is valid.