How many combinations of four digits are there using the numbers 0-9?

Question

And, is there a website that can produce a list of these combinations?

P.S. This has nothing to do with Soduko.

This isn't for homework, either. What teacher would assign his/her students to write 10,000 numbers down?

Answer 1

It is not 10000 combinations. For example, you could have 1234 and 4321. That's one combination. So, to figure this out . . . you use a textbook formula: n!/(r!*(n-r)!). It goes like this: 10!/(4!*(10-4)!) = 210 combinations. The calculator confirms this, because there's a function for this: 10 nCr 4 = 210. I don't know where you can find a program to generate the list for you, but I suspect there's one out there and I just can't find it right now. In summary, there's 210 combinations if no repeats are allowed and order is not important. There's 5040 permutations if repeats are not allowed but order is important, and 10000 permutations if repeats are allowed and order is important.

Answer 2

Here is how it works in general.
Repeats allowed: You can choose the first digit in any of 10 ways. similarly the second , third and forth so the total is 10 x 10 x 10 x 10 =10000.
Repeats not allowed: You can choose the first digit in any of 10 ways but for the second you only have 9 digits left and for the thied you have 8 so 10 x 9 x 8 x 7 =
If the number cannot start with zero: then 9 x 10 x 10 x 10. Technically 0321 is the same number as 321 which is not a 4 digit number but 0321 is a combination of 4 digits

Answer 3

There are 10,000 different combinations of four digits, if you are using the numbers 0-9.

10 times 10 times 10 times 10 equals 10,000
That's how you derive your answer.

Answer 4

Soduko

Answer 5

if the numbers can be recycled (ex: 1,1,1,1) then the possible combinations are 10,000. = 10x10x10x10

if the numbers cannot be recycled(ex: 1,2,3,4) then the possible combinations are 5,040. = 10x9x8x7

Now go do your homework WITHOUT cheating on the internet.

If you are looking for a correct textbook answer either of these will work. for a real answer then some of the others will but as is common there is a difference between theoretical and practical.

Answer 6

100

Answer 7

why cant we use the number 10?

well, only using 0-9 theres 10,000

Answer 8

10000

Answer 9

10000

Answer 10

9000 if you are referring to the meaningful numbers
10000 if you are merely combining things.