-5
720 (10*9*8)
8
59
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.
There are 8*8 = 64 such numbers.
The first 8 digit number is 10,000,000, the last is 99,999,999 which means there are 90,000,000 8 digit numbers
90
none
-5
You can make 4*3*2/2 = 12 numbers.
512
720 (10*9*8)
8
Eight (8) of them do.They are1221243642486384 .
59
9x9x8x7x6x5x4x3 =1632960