Question 883540
The first digit can be any one of (3, 4, 5, 6) since it can not be 2
The second digit can be any one of (2, 3, 4, 5, 6)
The third digit can be any one of (5, 6) if the second digit is a 2
The third digit can be any one of (2, 3, 4, 5, 6) if second digit is not a 2
The fourth digit can be a (6) if the second digit is a two and third digit is a 5
The fourth digit can be a (2, 3, 4, 5, 6) if the second digit is a two and third digit is a 6
The fourth digit can be one of (2, 3, 4, 5, 6) if the second digit is not a 2
Therefore we have
4 * 5 * 5 * 5 - (3 * 4 * 5) = 440