Question 984974
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There are 99 possible group numbers, 9999 possible serial numbers, 19 area numbers from 449-467 and 19 area numbers from 627 to 645. Total possible numbers:
(19)(99)(9999)+(19)(99)(9999)=37,616,238 possible numbers.
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With the area number restrictions lifted, there are other restrictions which limits the choices of the first three digits to a total of 753. for a total of possible numbers=(753)(99)(9999)=745,395,453. The population of the USA is currently about 320,000,000, so fewer than half of the possible number is utilized.
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If necessary in the future, restrictions on the 247 disallowed area numbers could be lifted, and the total possible numbers would be about a billion.