It is 5000
6751 would round up 6800 for the nearest hundred and 5373 would round up to 5400.
To the nearest ten, 4880 To the nearest hundred, 4900 To the nearest thousand, 5000
5000
5000
5000
5000
5000
5000
Half of 1000 is 500, so numbers in the range 5000 ± 500 round to 5000 to the nearest 1000 EXCEPT that numbers exactly half way round up. ie numbers greater than or equal to 5000 - 500 = 4500 and less than 5000 + 500 = 5500 will round to 5000 to the nearest 1000. So the largest whole number that rounds to 5000 to the nearest 1000 is 5500 - 1 = 5499.
5000
5000