180 of them.
500
There are 34 = 81 numbers.
27
pizza
There are 7,290 different 4-digit numbers that can be formed from the digits 1-9 without repetition.
There are 3024 of them.
180 of them.
There are 60480 numbers.
840
24
500
27 three digit numbers from the digits 3, 5, 7 including repetitions.
1 set
There are 5! = 120 such numbers.
There are 34 = 81 numbers.
Well, darling, if you're looking to form three-digit numbers using the digits 0 to 9, you've got 10 choices for the first digit (can't start with 0, honey), 10 choices for the second digit, and 10 choices for the third digit. So, that's 10 x 10 x 10, which gives you a grand total of 1000 possible three-digit numbers. Hope that clears things up for you, sugar!