# I hated math but I remember this mathematical problem, do you know the answer? **URL:** \ **Category:** Factual Questions\ **Created:** [June 29, 2003, 12:17am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055 "2003-06-29T00:17:14Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![sumwunsumwer](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@sumwunsumwer](https://boards.straightdope.com/u/sumwunsumwer)\ **Post date:** [June 29, 2003, 12:17am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/1 "2003-06-29T00:17:14Z")
If there were a 4 digit number using any combination of the numbers 0-9, HOW MANY POSSIBLE COMBINATIONS WOULD THERE BE? For example the last four digits of the social security numbers, how many numbers are possible there and how do you compute it? I had several ideas but thought surely someone knows exactly how to do this correctly…what better place then here to ask? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 29, 2003, 12:19am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/2 "2003-06-29T00:19:41Z")
10,000…the numbers from 0 to 9,999. ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [June 29, 2003, 12:22am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/3 "2003-06-29T00:22:26Z")
According to [this page,](http://newton.dep.anl.gov/askasci/math99/math99041.htm) there are 10,000 combinations. Reasoning given. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [June 29, 2003, 12:28am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/4 "2003-06-29T00:28:17Z")
10 possibilities for each digit, four digits total, gives you 10_10_10\*10 or 10[sup]4[/sup] or 10,000. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 29, 2003, 1:41am UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/5 "2003-06-29T01:41:10Z")
And, for completeness, if your combos also include letters, the number of possibilities is 36_36_36\*36, or 36^4, or just short of 1.7 million. The “why” is 10 numbers (0-9) plus 26 letters (a-z). If you allow mixed case, the choices become 0-9 plus a-z plus A-Z, (10+26+26) – 62^4 = just under 14.8 million combinations. ---
**Author:** ![sumwunsumwer](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@sumwunsumwer](https://boards.straightdope.com/u/sumwunsumwer)\ **Post date:** [June 29, 2003, 11:15pm UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/6 "2003-06-29T23:15:11Z")
10,000 makes sense…I thought so but had another person tell me that was not correct. Thanks 🙂 ---
**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\ **Post date:** [June 29, 2003, 11:26pm UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/7 "2003-06-29T23:26:04Z")
One could argue that the answer is 9999, but that’s if you forget (or exclude) 0. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [June 29, 2003, 11:42pm UTC](https://boards.straightdope.com/t/i-hated-math-but-i-remember-this-mathematical-problem-do-you-know-the-answer/185055/8 "2003-06-29T23:42:27Z")
Although the person making that argument doesn’t really have a leg to stand on…