![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
Situation:
\Selecting ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0d25261cbf81e1c8bf5afdeff1f7b3e9.png\")
books to read from a list of ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=596dbfdc822a43adb27d19f5c360ac2a.png\")
.
Conclusion:
\Total number of books are ,then ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=980033c88c41e3e9d92b7422ac973a99.png\")
.
From the total books selecting by ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0d25261cbf81e1c8bf5afdeff1f7b3e9.png\")
books, So ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=df77da64242c2f90ea2e2b265f35261b.png\")
.
Combination:
\A selection of objects in which order is not important is called a combination.
\Therefore, the situation is combination because the selecting books does not matter.
\![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
Combination.