0
How many seven digits number can be made from numbers 123456789 but no repititions are allowed?
Wiki User
∙ 12y ago
181440 possible numbers.
9 choices for first digit, leaving
8 choices for the second digit for each of these choices for the first digit, leaving
7 choices for the third digit for each of these choices for the second digit, leaving
...
3 choices for the seventh digit for each of these choices for the sixth digit, giving
9 x 8 x 7 x ... x 3 = 181440 possible numbers.
More generally, when there are n different items and r need to be selected from them in order it is called a permutation and the number of ways of doing this is:
nPr = n!/(n-r)!
where the exclamation mark means "factorial" which is the product of all numbers from 1 to the number, that is n! = n x (n-1) x (n-) x ... x 2 x 1.
In this case, there are n=9 items and r=7 need to be selected giving:
9P3 = 9!/2! = 9 x 8 x ... x 3 = 18144
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
How many 3-digit numbers can be formed from digits 123456789?
-123456786
How many digits numbers each less than 500 can be formed from the digits 13467 if repetitions is allowed?
There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.
How many 13 digit numbers are possible by using the digits 12345 which are divisible by 4 if repetition of digits is not allowed?
If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
How many 9 digit combinations can be made from the numbers 123456789?
If the numbers are not allowed to repeat themselves then 362,880. * * * * * That is the number of permutations, not combinations. In a combination the order of the digits does not matter. So there is only one 9-digit combination.
How many 3 digit numbers can be formed from the digits 1234?
64 if repetition is allowed.24 if repetition is not allowed.
How many 2-digit numbers can be produce using the digits 123456789 if repetition is not allowed?
-123456787
How many 4 digit numbers can be formed from digits 123456789?
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
How many 6 digit numbers can be formed using the digits 123456789?
There are 60480 numbers.
How many 4 digit numbers can be formed from the digits 123456789?
There are 3024 of them.
What is 1234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567?
A repeating sequence of numbers ! The digits 123456789 are simply repeated over and over.
What numbers 123456789 called?
The individual symbols, if that's what you mean, are called digits. That includes the zero, as well.
How many of the digits in 123456789 are factors of 123456789?
1, 3 and 9
How many 4-digit numbers can be formed from digits 123456789?
-123456785
What four digit number is divisible by 123456789 with a remainder of one?
A number divisible by 123456789 must be 0 or bigger than 123456789. It must, therefore have 1 digit or 9 digits (or more). A remainder of 1 makes no difference to the number of digits. In any case, there can be no number of 4 digits that is divisible by 123456789.
How many 3-digit numbers can be formed from digits 123456789?
-123456786
How many digits numbers each less than 500 can be formed from the digits 13467 if repetitions is allowed?
There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.
How many 13 digit numbers are possible by using the digits 12345 which are divisible by 4 if repetition of digits is not allowed?
If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
