The critical bit of information: the number after "nearest" is missing from the question.
Anything from 2500 to 3499
It could be any number whatsoever.
45,46,47,48,49,50,51,52,53,54
Since 770 is a whole number, it is already rounded to the nearest thousandth. Or could it be 770.000?
14,999.99... , to the nearest ten thousand.
Anything from 2500 to 3499
10001/999900
1000
If a number rounds to 600,000 when rounded to the nearest hundred thousand, it could be any number between 550,000 and 649,999. This is because when rounding to the nearest hundred thousand, any number from 550,000 to 649,999 would round up to 600,000.
You could be 1555
It could be any number whatsoever.
45,46,47,48,49,50,51,52,53,54
Anything from 495 to 504
3.60
Since 770 is a whole number, it is already rounded to the nearest thousandth. Or could it be 770.000?
14,999.99... , to the nearest ten thousand.
333.3333333333, for example.