![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
Select two different natural numbers and then determine whether
\the product is a natural number.
\\
Try some examples.
\![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=fa41c8746dff84eb526f5ca7eb149f1c.png\")
\ \
![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f0f8cf5791952f8762edaf74a5bbc0b9.png\")
\ \
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![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a45cc3832b10ecaef257b55d0be9568d.png\")
Since the products of each pair of natural numbers are natural numbers, the set of natural numbers is closed under multiplication.![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
The set of natural numbers is closed under multiplication.
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