24
When using the numbers one through seven, the total number of different combinations depends on how many numbers you want to select. If you're looking for all possible combinations of any length (from one to seven), you can calculate it using the formula for combinations, which is (2^n - 1) (where (n) is the total number of items) to account for all subsets except the empty set. Therefore, for seven numbers, there are (2^7 - 1 = 127) different combinations. If you specify a particular number of selections, the calculation would differ accordingly.
You can select 9 numbers for the first digit, 8 numbers for the second digit, and 7numbers for the third digit; so 504 (e.g. 9*8*7) different three digit numbers can be written using the digits 1 through 9.
9
No 5291 is not a prime using 2 numbers. It is a prime using three numbers.
89,999 different numbers i guess
1000
You have seven different digits (symbols) to choose from, so you can form seven different one digit numbers and 7×7=72=49 different two digit numbers.
1 x ((7 x 3) + 3) = 24
You can select 9 numbers for the first digit, 8 numbers for the second digit, and 7numbers for the third digit; so 504 (e.g. 9*8*7) different three digit numbers can be written using the digits 1 through 9.
9
No 5291 is not a prime using 2 numbers. It is a prime using three numbers.
89,999 different numbers i guess
There are 3*2*1 = 6 of them.
You can make twelve using three different numbers by adding 1, 4, and 7 together: 1 + 4 + 7 = 12. Another combination could be 2, 3, and 7: 2 + 3 + 7 = 12. You can also use 3, 4, and 5: 3 + 4 + 5 = 12.
6 possible 3 digit combonations
Using 1, 2, and 3, you can make 27 whole numbers.
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.