450 whole numbers.
90
There are no 3-digit whole numbers whose digits sum to 3. The smallest 3-digit number is 100, and the largest is 999, but in neither case is the sum of the digits equal to 3.
999-99=900
24.
450 whole numbers.
There are 900 three-digit whole numbers between 1 and 1000
90
1, 2, 3, 4, 5, 6, 7, 8 and 9 are all 1 digit whole numbers
There are no 3-digit whole numbers whose digits sum to 3. The smallest 3-digit number is 100, and the largest is 999, but in neither case is the sum of the digits equal to 3.
999-99=900
24.
Assuming you mean whole numbers and leading zeros do not count, the smallest 3 digit number is 100.
3 digit numbers are lessthan 4 digit numbers
3
-21
13, 23, 43, 53, 73, and 83