







Three digit codes 
20190714 

From Jessica: I need to find the total number of 3 digit codes using the digits 1 through 9. How many of these codes would be odd numbers, and how many even? Answered by Penny Nom. 





4 digit codes 
20190227 

From Sophia: How many 4 digit codes can you get out of a numbered key pad ? Answered by Penny Nom. 





My phone is "sim locked" 
20100610 

From Daniel: Question from daniel:
got a phone that says sim locked, it requires 09 digit code to get in, how many combinations could there be if you could please list the possibilities, the number can be repeated. Answered by Penny Nom. 





Zip codes, postal codes and 5 digit codes 
20080708 

From Mike: Sorry if you have answered this before but I don't understand the explanations I have seen.
How many possible combinations are in a 5 digit code (like a Zip Code). Is there an equation that can be used for this type of question? Answered by Penny Nom. 





Zip codes 
20071203 

From Natalie: How many 5 digits zip codes are possible if digits can be repeated? Answered by Penny Nom. 





How many three button codes are possible? 
20070823 

From kim: A home security device has ten buttons and is disarmed by pushing three buttons in sequence. How many three button codes are possible if each button can be pushed more than once in the code? Answered by Stephen la Rocque. 

