how many possible combinations for phone numbers?
156130
Each three-digit area code has a capacity of 7,919,900 telephone numbers: NXX may begin only with the digits [2–9], providing a base of eight million numbers: (8 × 100 × 10000). However, to avoid confusion with the N11 codes, the last two digits of NXX cannot both be 1.
966160
Hence, in this case there are 4 3 = 12 possible two digit numbers. For the third digit there are only 2 choices and for the last digit, one choice. Thus if you are not allowed to repeat a digit the number of possible 4 digit numbers you can construct from 1,2,3,4 is 4 3 2 1 = 24.
178666
There are one million of them (999999 + 1). If repetition is not allowed (which is probably what you are referring to in your last sentence), you can pick any of ten digits for the first number, any of the nine remaining for the second, and so forth. This is 10 times 9 times 8 times 7 times 6 times 5 or 151,200.
85182
For each choice of the first two digits you have 10 choices for the third digit. Thus you have 10x10x10 = 1000 choices for the first three digits. Finally you have 10 choices for the fourth digit and thus there are 10x10x10x10 = 10 000 possible 4 digit combinations from 0-9.
10234
There are 10,000 possible combinations that the digits 0-9 can be arranged into to form a four-digit code.
794598
There are 40,475,358 possible 6-number combinations that can be formed from numbers 1-58 . To determine this, the Combination formula is used. n choose k equals the factorial of n (divided by) all over the factorial of k times (or multiplied by) the factorial of n minus k.
1372280
Each three-digit area code may contain up to 7,919,900 unique phone numbers: NXX may begin only with the digits [2–9], providing a base of 8 million numbers: ( 8 x 100 x 10000 ) . However, the last two digits of NXX cannot both be 1, to avoid confusion with the N11 codes (subtract 80,000).
431600
We conclude that there are 35−3×25+3=150 combinations. If there were no restrictions, the number of five digit codes that could be formed with the digits 1, 2, 3 would be 35 since there are three ways to choose each of the five digits.
130300
The number of 5-digit combinations is 10 5=100,000. So, one more than 99,999. You can generalize that: the number of N-digit combinations is 10 N.
65463
It is the number of ways to choose 3 of the 10 digits in which order is not important. There are 6 = 3x2x1 ways to order 3 digits in a row. Thus the number of combinations of 3 of the 10 digits is 720/6 = 120 combinations.
1439257
There are 10,000 possible combinations. Start at 0001, then 0002, then 0003...and work your way to 9999. Don't forget to try 0000 as well. You can also start at 9999 and work your way down to 0000 if you'd rather.
432059
using 1 to 50 there are 50 possible one-number combinations. With 49 cards left over, there are 50x49 two-number combinations, 50x49x48 three-number combinations, and 50x49x48x47 four-number combinations.
1116347
Dana F Anderson, Just interested in math is all. Kinda a hobby. Assuming the digits 0 through 9 can be used, and a number can be repeated in the combination, then there are 10^3 possible combinations (1000 - from 000 to 999). If three different numbers have to be used, then 10 x 9 x 8 = 720 possible combinations.
1422119
There are 40,475,358 possible 6-number combinations that can be formed from numbers 1-58 . To determine this, the Combination formula is used.
184905
Included with Your Order: All Possible 6/49 Number Combinations. Total Combinations - 13,983,816. 50K-1M number combinations per file.
1092906
The number of possible combinations that are possible with 26 letters, with no repetition, is 67,108,863.
631803
Each three-digit area code has a capacity of 7,919,900 telephone numbers: NXX may begin only with the digits [2–9], providing a base of eight million numbers: (8 × 100 × 10000).