document.write( "Question 1148666: There are 4 different mathematics books and 5 different science books in how many ways can the books be arranged on a shelf if?
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Algebra.Com's Answer #770017 by ikleyn(52781)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "If WHAT ?\r
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document.write( "Without any \"if\", 4 + 5 = 9 different items can be arranged in 9! = 9*8*7*6*5*4*3*2*1 = 362880 ways.     ANSWER\r\n" );
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document.write( "It is the number of PERMUTATIONS of 9 different items.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On Permutations,  see introductory lessons \r
\n" ); document.write( "\n" ); document.write( "    - Introduction to Permutations\r
\n" ); document.write( "\n" ); document.write( "    - PROOF of the formula on the number of Permutations\r
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\n" ); document.write( "\n" ); document.write( "    - OVERVIEW of lessons on Permutations and Combinations\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic  \"Combinatorics: Combinations and permutations\". \r
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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