Let's consider the two cases:

Case 1: N is a 3-digit number
In this case, (N+30) is a 4-digit number. So, exactly one of them is a 3-digit number. The smallest 3-digit number is 100, and the largest is 999. So, there are 900 possible values of N in this case.

Case 2: (N+30) is a 3-digit number
In this case, N is either a 2-digit or a 1-digit number. If N is a 2-digit number, then (N+30) is also a 2-digit number, which is not possible. So, N must be a 1-digit number. The possible values of N are 1, 2, …, 6. For each value of N, we get a unique value of (N+30), which is a 3-digit number. So, there are 6 possible values of N in this case.

Therefore, the total number of integers N that satisfy the given condition is 900 + 6 = 906.