Answer:
600
Explanation:
The number has 4 digits.
The first digit can be 1, 2, 3, 4, 5.
The second through fourth digits can be 1, 2, 3, 4, 5, 6, 7.
There are 5 choices for the first digit, 6 choices for the second digit, 5 choices for the third digit, and 4 choices for the fourth digit.
5 × 6 × 5 × 4 = 600