document.write( "Question 1206217: (a) How many seven-digit telephone numbers are possible if the first digit must be nonzero?
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\n" ); document.write( "9000000\r
\n" ); document.write( "\n" ); document.write( "(b) How many international direct-dialing numbers for calls within the United States and Canada are possible if each number consists of a 1 plus a three-digit area code (the first digit of which must be nonzero) and a number of the type described in part (a)? \n" ); document.write( "
Algebra.Com's Answer #843499 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "I found this online:\r\n" );
document.write( "Using 0 or 1 as the first digit of an area code or central office \r\n" );
document.write( "code is invalid, as is a 9 as the middle digit of an area code; \r\n" );
document.write( "these are trunk prefixes or reserved for North American Numbering \r\n" );
document.write( "Plan expansion.\r\n" );
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document.write( "Perhaps you should mention this to your teacher.\r\n" );
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document.write( "The trick for finding how many integers there are from A to B, inclusive,\r\n" );
document.write( "is to subtract 1 less than the smallest from both the smallest and the largest:\r\n" );
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document.write( "You got the first correct, if you ignore the above.\r\n" );
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document.write( "100-0000 to 999-9999, or without the hyphen:\r\n" );
document.write( "1000000 through 9999999\r\n" );
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document.write( "Subtract 1 less than the smallest, or 999999 from each\r\n" );
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document.write( "That's the integers 1 through 9000000.  You got that.\r\n" );
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document.write( "Doesn't the (b) part mean that you just put a 1 before each of those in the\r\n" );
document.write( "(a) part?  Wouldn't it just be the same number?\r\n" );
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document.write( "Edwin
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