Are the groups $(\Bbb Q^2,+)$ and $(\Bbb Q,+)$ isomorphic?

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Are the groups $(\Bbb Q^2,+)$ and $(\Bbb Q,+)$ isomorphic ?

I don't know how to proceed because I am getting all the structural properties same.

Can I get some help?

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A key property of $\mathbb{Q}$ as an additive group: any two nonzero elements are commensurable. That is, for any nonzero $a,b$, they are both integer multiples of some common divisor $c$.

This is not true of $\mathbb{Q}^2$; $(1,0)$ and $(0,1)$ are incommensurable.

Therefore, the two groups are not isomorphic.