1100
1138 rounded to the nearest 100 would be 1100. When rounding to the nearest 100, you look at the digit in the tens place (1 in this case) and determine if it is 5 or greater. Since 1 is less than 5, you keep the hundreds place (1) the same and change all other digits to the right to 0.
853 rounded to the nearest 100: 900. 10853 rounded to the nearest 100: 10900.
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
100
100
0
9000
884600