Well honey, in numbers 1 through 50, each digit from 0 to 9 appears 5 times. It's simple math, darling. Just divide the total number of digits by 10 and you'll get your answer. Now go impress someone with your newfound knowledge, you're welcome!
It would help to know which digit. 0 appears in 9 numbers and each of the others in 18 numbers.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
Each digit can appear in each of the 4 positions. There are 9 digits, therefore there are 9⁴ = 6561 such combinations.
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.
10!/3! = 604800 different combinations.
It would help to know which digit. 0 appears in 9 numbers and each of the others in 18 numbers.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
The 3 digit numbers under 500 are 100 through 499.
Just think of how many possibilities you have for each digit. 10x9x8x7x6x5x4x3x2 or 10 factorial is 3 628 800.
5 x 10 x 5 = 250 different numbers, assuming there is no limit to each digits' use.
Each digit can appear in each of the 4 positions. There are 9 digits, therefore there are 9⁴ = 6561 such combinations.
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
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.
ten factorial = 10! = 3,628,800
six
10!/3! = 604800 different combinations.
10999