How many combonations of numbers are there in for a telephone number (not including the area code?)
2006-09-29 11:56:46 · 8 answers · asked by Wei H 2 in Science & Mathematics ➔ Mathematics
Please explain how you got the answer
2006-09-29 12:01:54 · update #1
SORRY w/ NO repeating numbers too!
2006-09-29 12:05:45 · update #2
( ALL numbers included, NO REPEATS OF NUMBERS THOUGH)
2006-09-29 12:20:56 · update #3
YOu cannot do 281-444 -3422 because numbers repeat in that number ( No repeats)
2006-09-29 12:26:38 · update #4
phone #'s are 7 digits.
for the 1st digit, you have 10 choices.
for the next, you have 9, then 8 etc.
total=10*9*8*7*6*5*4=604,800
2006-10-02 17:11:26 · answer #1 · answered by yupchagee 7 · 16⤊ 0⤋
Assuming you're talking about USA phone numbers, there are 7 digits (not including the area code). The first digit can't be zero or one, so there are 8 possibilities for that digit. Each of the other digits can be one of the remaining ones, so there are 9 possibilities for the 2nd digit, 8 for the 3rd, etc.
So the number of combinations should be 8 * 9 * 8 * 7 * 6 * 5 * 4 = 483,840, unless there are other rules I don't know about. :)
Hope that's what you're looking for.
2006-09-29 12:05:11 · answer #2 · answered by Jay H 5 · 0⤊ 0⤋
Actually there would be 8 million since 0 and 1 are special and can't be used to lead.
2006-09-29 12:06:55 · answer #3 · answered by feanor 7 · 0⤊ 0⤋
It's something to the multiple of 10 becuause 0-9 is 10 numbers.....
2006-09-29 12:05:58 · answer #4 · answered by James I 2 · 0⤊ 0⤋
10,000,000, if the number takes the form xxx-xxxx and all numbers are allowed. In actuality many exchanges are not allowed, and phone numbers in the US start with 201 (I think). Exchanges like 411, 555 and 911 are also not used.
2006-09-29 12:00:09 · answer #5 · answered by Pseudo Obscure 6 · 0⤊ 0⤋
Well no I have 8 digit phone number !
2016-03-18 02:49:07 · answer #6 · answered by Anonymous · 0⤊ 0⤋
i think its 9 factorial to te power 9
2006-09-29 12:02:13 · answer #7 · answered by Teen-sensible! 2 · 0⤊ 0⤋
9x9x9x9x9x9x9x9x9x
2006-09-29 12:04:38 · answer #8 · answered by julean33 2 · 0⤊ 0⤋
604,800
2006-10-07 04:06:43 · answer #9 · answered by smiley 1 · 0⤊ 0⤋