How does mathematics understand the password composed of four digits, just the combination of the fourth power of 10?
Each number has ten possible answers (0-9, *** 10 numbers). If it is a two-digit number, there are 10 possibilities in both positions. For example, the single digit number is 0, and the ten digit number can have 10. The unit number is 1, and ten digits can also correspond to ten digits, so the answer to the two-digit password is 10* 10, which is the quadratic of 10; Similarly, the three-digit password is 10 */kloc-0 *10, which is the cube of10, and the four-digit password is 10* 10.