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
6 possible 3 digit combonations
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.
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.
3.1415926