Look at the number in the hundreds place right now. Then look at the number to the right of it. If that number is a 5 or greater, then you'd increase the number in the hundreds place by 1. And make the rest zeros.
But if the number is less than 5, you'd leave the number in the hundreds spot alone and make the rest zeros.
390
490
492. 4920 rounded to the nearest 100th place = 4900
853 rounded to the nearest 100: 900. 10853 rounded to the nearest 100: 10900.
600
490
100
100
0
555 rounded to the nearest 100 is 600.
97 rounded to the nearest hundred is 100. 97 rounded to the nearest ten is 100
100