What numbers would round to 520000 if rounded to the nearest ten thousand?

When rounding to the nearest ten thousand half round up and half round down. Thus 10,000 ÷ 2 = 5,000 numbers either side of 520,000 round to it, ie 520,000 ± 5,000. However, as numbers exactly halfway round up:

Thus any number greater than or equal to 515,000 and less than 525,000 round to 520,000 to the nearest ten thousand.