If you don't use any digit more than once, there are 83 combinations: 418 417 412 419 410 413 416 487 482 489 480 483 486 472 479 470 473 476 429 420 423 426 490 493 496 403 406 436 187 182 189 180 183 186 172 179 170 173 176 129 120 123 126 190 193 196 103 106 136 872 879 870 873 876 829 820 823 826 890 893 896 803 806 836 729 720 723 726 790 793 796 703 706 736 290 293 296 203 206 236 903 906 and 936
A three digit number is any counting number between 100 and 999 (inclusive). It is made up of three digits, the first of which cannot be 0.
6*7*7 = 294
24
A 5-digit combination can be obtained as:five 1-digit numbers from 1-9,three 1-digit numbers from 1-9 and one 2-digit number from 10-39, orone 1-digit number from 1-9 and two 2-digit numbers from 10-39.There are 9C5 = 126 of the first kind,9C3*30C1 = 84*30 = 2520 of the second, and 9C1*30C2 = 9*435 = 3915 of the third.All together, there are 126 + 2520 + 3915 = 6561 5-digit combinations.
There are 900 natural numbers made up of only three digits. This is because there are 9 options for the first digit (1-9), 10 options for the second digit (0-9), and 10 options for the third digit (0-9). Multiplying these options together gives us 9 x 10 x 10 = 900 possible three-digit natural numbers.
Six combinations if you use each digit only once per combination: 157 175 517 571 715 and 751.
A three digit number is any counting number between 100 and 999 (inclusive). It is made up of three digits, the first of which cannot be 0.
24 three digit numbers if repetition of digits is not allowed. 4P3 = 24.If repetition of digits is allowed then we have:For 3 repetitions, 4 three digit numbers.For 2 repetitions, 36 three digit numbers.So we have a total of 64 three digit numbers if repetition of digits is allowed.
1
999
6*7*7 = 294
24
6 ways: 931,913,139,193,391,319
A 5-digit combination can be obtained as:five 1-digit numbers from 1-9,three 1-digit numbers from 1-9 and one 2-digit number from 10-39, orone 1-digit number from 1-9 and two 2-digit numbers from 10-39.There are 9C5 = 126 of the first kind,9C3*30C1 = 84*30 = 2520 of the second, and 9C1*30C2 = 9*435 = 3915 of the third.All together, there are 126 + 2520 + 3915 = 6561 5-digit combinations.
There are two choices for the first digit ... 1 or 2. For each of those . . .The second digit can be any one of the three choices. For each of those . . .The third digit can be any one of the three choices. For each of those . . .The fourth digit can be any one of the three choices. For each of those . . .The fifth digit can be any one of the three choices.The total number of possibilities is (2 x 3 x 3 x 3 x 3) = 162
If this is a homework assignment, please consider trying it yourself first, otherwise the value of the reinforcement to the lesson offered by the homework will be lost on you.There are 60 possibilities that can be made for a three digit number using the numbers 2 4 6 8 and 9. (5 choices for the first digit, 4 choices for the second digit, and 3 choices for the third digit - multiply 5, 4, and 3, and you get 60.)To determine how many of these three digit numbers are smaller than 500, consider that, given 2 4 6 8 and 9, the first digit would have to be 2 or 4. That gives 2 choices for the first digit, 4 choices for the second digit, and 3 choices for the third digit. Multiply 2, 4, and 3, and you get 24.
There are 720 combinations if you use each of the digits only once per combination.