If you were told to round two digit numbers to the closest 100, you could round everything from 10-99 to the nearest 100, inclusive of 10 and 99. I.e all two-digit numbers round up to 100. This is because "to the nearest hundred" does not mean "up to 100, or down to zero", since "zero" is not in the "hundred's" catagory. i.e you can only round up to 100.
This means you have 89 seperate two-digit number which will round up to 100.
100
The 3 digit numbers under 500 are 100 through 499.
900
9
100 to 900
There are 90 two-digit whole numbers between 1 and 100.
100
98600
There are 900 three-digit numbers, ranging from 100 to 999.
there are 50 prime numbers between 1-100 and of them 2,3,5,7 are single digit so that would leave 46 double digit prime numbers between 1-100
59
The digit appears eleven time from 1 to 100.