Any number between 250 and 350 - including 250, but not including 350 (depending on the exact rules used, actually).
296, 297, 298, 299
251 252 348 349
300
300
300
320 rounded to the nearest hundreds is 300
300
300
300
270 rounded to the nearest hundred is 300.
300
300
300
It is 300 when rounded to the nearest hundred