Discussion Forum
Que.  The set of positive integers under the operation of ordinary multiplication is: 
a.  not a monoid 
b.  not a group 
c.  a group 
d.  an Abelian group 
Answer:an Abelian group 
Nibedita Roy :(April 12, 2019)
sir how it is abelian group. can u explain it.

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Ashutosh :(June 22, 2019)
Inverse is not available in case of Z+. for eg 3 belongs to Z+ but 1/3 doesn't. Therefore it is not a group.

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