Solution
= Solution
Subtraction fails <associativity>: $(0*0)*1=-1$ but $0*(0*1)=1$. Thus it violates the <group axioms> and is \b[not a group]. It has a right identity $0$, but no element can be a two-sided <identity element>.
= Solution
Subtraction fails <associativity>: $(0*0)*1=-1$ but $0*(0*1)=1$. Thus it violates the <group axioms> and is \b[not a group]. It has a right identity $0$, but no element can be a two-sided <identity element>.