document.write( "Question 323579: Find the least number which is both a multiple of 20 and a multiple of 21. \n" ); document.write( "

Algebra.Com's Answer #231526 by Edwin McCravy(20059) $\"\"$ $\"About$

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document.write( "Find the least number which is both a multiple of 20 and a multiple of 21\r\n" );
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document.write( "20 = 4x5 = 2x2x5\r\n" );
document.write( "21 = 3x7\r\n" );
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document.write( "The prime factors of 20 are two 2's and one 5\r\n" );
document.write( "Te prime factors of 21 are one 3 and one 7.\r\n" );
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document.write( "Since there are no common prime factors, the LCM (least common multiple)\r\n" );
document.write( "is just their product 20x21 = 420.\r\n" );
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document.write( "Edwin

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