Question

A social security number contains nine digits, such as 952-56-7606. How many different social security numbers can be formed?

Answer 1

First spot: 9 choices (0-9)

Second spot: 9 choices (0-9)

Third spot: 9 choices (0-9)

.

.

.

Ninth spot: 9 choices (0-9)

There are 9 choices for each digit, meaning we need to compute 9^9 to figure out how many possible social security numbers there are.

Explination:

9^9 = 387420489 possible social security numbers