You have 9 options for the first digit; whichever digit you choose you have 8 options for the second digit, 7 for the third digit, 6 for the fourth digit - so you have a total of 9 x 8 x 7 x 6 different combinations. Sure I could make a list, but that would be rather boring - and utterly useless as well.
3.918208205 X 10^11 I think but I'm stupid so probably wrong
== I suggest starting with a pen and a piece of paper. == Any number which is above 9 isn't a digit (in denary) None of the numbers from 1 to 45 are 7 digits long
There are 27 possible combinations.
106 or a million.
The number of four-digit combinations is 10,000 .Stick a '3' before each of them, and you have all the possible 5-digit combinations that start with 3.There are 10,000 of them. They run from 30,000 to 39,999 .
90
3.918208205 X 10^11 I think but I'm stupid so probably wrong
As the number has to start with 15, we have only 3 remaining digits to work with. There are 3 possible options for the first digit. Then out of each of these, 2 possible options for the second digit, and one option for the last. This means that in total there are 3x2x1 (6) possible combinations. These are: 15234 15243 15324 15342 15423 15432
There are 210 4 digit combinations and 5040 different 4 digit codes.
You don't mean "3 possible digit combinations"; you mean "3-digit possible combinations"and you also forgot to specify that the first digit can't be zero.(We wouldn't have known that, but two of your buddies asked the same questionabout 7 hours before you did.)The question is describing all of the counting numbers from 100 to 999.That's all of the counting numbers up to 999, except for the first 99.So there are 900 of them.
== I suggest starting with a pen and a piece of paper. == Any number which is above 9 isn't a digit (in denary) None of the numbers from 1 to 45 are 7 digits long
There are 5,040 combinations.
105 = 100000
When a number is a multiple of 5, the possible values of the ones digit are zero and five.
56 combinations. :)
I can't
There are 27 possible combinations.