Bankcards are often secured using a 4-digit personal identification number (PIN). Automated Teller Machines (ATMs) allow users three attempts to get the correct PIN before they lock the user out and confiscate the bankcard. Use the Fundamental Counting Principle to determine the total number of possible 4-digit PIN numbers  

The total number of possible 4-digit PIN numbers is 10 000.

 

A natural question arises from this answer. How can the bank provide PINs to all its customers with only 10 000 from which to choose? Recognizing that 10 000 represents all the choices from which the individual can choose with his or her specific card is important. More than one person can use the same PIN.

 

Read pages 68-69 Examples 1 and 2 in your textbook, Principles of Mathematics 12.

Complete the Your Turn questions on page 68 (a & b) and page 69 for more practice solving counting problems.

Click here to verify your answers .

 

Watch  The Counting Principle video to see more examples of solving counting problems.