Math.ceil() is the correct function to call. I’m guessing a is an int, which would make a / 100 perform integer arithmetic. Try Math.ceil(a / 100.0) instead.
int a = 142;
System.out.println(a / 100);
System.out.println(Math.ceil(a / 100));
System.out.println(a / 100.0);
System.out.println(Math.ceil(a / 100.0));
System.out.println((int) Math.ceil(a / 100.0));
Outputs:
1
1.0
1.42
2.0
2
See http://ideone.com/yhT0l