So you can look at the first digit of each number: you have a 3, 2, 3. You know 2 is less than three. So 2,965,006 is the smallest number. You had two numbers where 3 was the first digit, so you look at the next number: a 5 and 2. 2 is smaller than 5, so 3,261,636 will be the next smallest.
Overall, least to greatest is:
2,965,006; 3,261,636; and finally 3,516,235 :)