document.write( "Question 748579: Robin has 21 books on computers. She donates z of them to the school library. How many does she have left? \n" ); document.write( "
Algebra.Com's Answer #455516 by Cromlix(4381)\"\" \"About 
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(21 - z)would be the number of books left. \n" ); document.write( "
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