Question

How many 3-digit passwords can be formed from the digits 0 through 9

Answer 1

Answers 729 900 1,000 
This is asking "how many numbers are there from 0 to 999 ? " :)
(remember to include 0)
They want all the passwords from 000 through 999 So that's 10 choices for each of the three places. 10^3 = 1000. :) or just list them all 000 001 002 003 ... 997 998 999 Which is 1,000 total codes.