







Some strings of 4 digits 
20200626 

Judy pose la question : I wrote previously and need more help. I need to generate a list of 4 digit. Numbers using 09 with no repetitions
I know that there is a 6 followed by a 2. Order does matter
Thank you in advance for your help. Penny Nom lui répond. 





Four digit numbers 
20160908 

ning pose la question : 00009999 there is ten thousand 4digit numbers. How to find the number of ways that 4 digit are the same? How to prove it by using formula? Penny Nom lui répond. 





A six digit code 
20160506 

Ralph pose la question : How many combinations are possible if a "safe" has four buttons and you can use a six digit code? (these are just single press buttons..)For example, this could be one possible combination: Button 4 Button 1 Button 1 Button 3 Button 2 Button 4. Thanks! Penny Nom lui répond. 





Four digit phone numbers 
20140225 

Tom pose la question : Hi, I'm an online math teacher, working on lessons for my students.
This question is in their book and I can't do it...! Help!
It has to do with phone numbers, and in this problem,
we are only dealing with
the last 4 digits of the number.
It asks how many possible numbers we have
if at least one digit repeats in the last 4 digits of the number. Penny Nom lui répond. 





A 4 digit code 
20130326 

chris pose la question : I saw a previous question about a 4 digit code type thing and I was wondering if you could email me that same type of thing.
I changed the pin number on my phone's lock screen and I tried hard to remember it, then I had to go help my mom with something and I automatically forgot it and there is no way for me to get back on my phone.
I need all of the possible 4 digit number combinations without the numbers 0, 1, or 2. It cannot be repeating, ascending, or descending.
I know you may not want to do all of them, but I really need it. Robert Dawson lui répond. 





Four digit "combinations" using 0124 
20130227 

Ayana pose la question : What are all the possible four digit combinations using 0124. Please list them for me. Thank you. Penny Nom lui répond. 





A 4 digit phone lock using the digits 4, 2, 3 and 0 
20121224 

Ragu pose la question : I would like to know formula for searching a combination of 4 digit. eg.
I knew my Phone Lock combination is my car plate number 4230. But
this time, i used another way around instead of 4230.
But I am sure, there is only this 4 digits only. 4 & 2 & 3 & 0 Penny Nom lui répond. 





What numbers can I be? 
20101113 

john pose la question : my thousands digit is 2 times my ones digit.my hundreds digit is my ones digit plus 2. my tens digit is the difference between my thousands and hundreds digit what numbers can i be? Penny Nom lui répond. 





Four digit numbers 
20100522 

tyeisha pose la question : Whats all the four digit numbers you can come up with using numbers 09 Tyler Wood lui répond. 





Fourdigit combinations 
20090418 

Carri pose la question : How many 4digit combinations can be made out of digits 1, 2, 3, 4, & 5 using each number once? What are the combinations? Penny Nom lui répond. 





Four digit numbers 
20090310 

Theresa pose la question : I need to know the number of 4 digit numbers that can be formed using 1234 without repeating numbers Penny Nom lui répond. 





Four digit numbers using 1, 0, 2 and 8 
20090127 

Mike pose la question : How many combinations of this four digit number 1028 can this produce only using those numbers. Example would be 0000, 0001,0002,0008,0010,0011,0012,0018,etc... Penny Nom lui répond. 





A four digit passcode 
20090112 

john pose la question : i have a machine at home that has a four digit passcode and the numbers range from 1 to 4 how can i get all the ways those numbers can be used Harley Weston lui répond. 





Four digit palindromes 
20030505 

Heather pose la question : How many palindromes were in between the numbers 1000 and 9999? Penny Nom lui répond. 





4 x abcd = dcba 
20021120 

A student pose la question : Say you have a four digit number (e.g. abcd) and you multiply the number by 4. The answer you get will be the reverse order of the number you started with (dcba). What is the number? The four digits (a,b,c,d) cannot be the same number or cannot be repeated. Penny Nom and Claude Tardif lui répond. 

