Roundoff Riddle

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.




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First four digits are divisible by 4.
First five digits are divisible by 5.
First six digits are divisible by 6.
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First eight digits are divisible by 8.
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The black one says, 'We have 28 legs altogether.'

The green one says, 'We have 27 legs altogether.'

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Servants with multiple legs

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