Check the commutativity and associativity of each of the following binary operations:

‘*’ on N defined by a*b = ab for all a,bN

Given that * is a binary operation on N defined by a*b = ab for all a,bN.


We know that commutative property is p*q = q*p, where * is a binary operation.


Let’s check the commutativity of given binary operation:


a*b = ab


b*a = ba


b*a≠a*b


Commutative property doen’t holds for given binary operation * on N.


We know that associative property is (p*q)*r = p*(q*r)


Let’s check the associativity of given binary operation:


(a*b)*c = (ab)*c


(a*b)*c = (ab)c


(a*b)*c = abc ...... (1)


a*(b*c) = a*(bc)


...... (2)


From (1) and (2) we can clearly say that associativity doesn’t hold for the binary operation ‘*’ on ‘N’.


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