on Page 90, sample test 2, problem 62:

Let R be a ring and let x<>0 be a fixed element in R. Which of the followin is a subring of R?

In the choices, there is one {nx|n is an integer}.

I think this is a subring, since rings do not have to be closed under multiplication. However, the answer gives no.

Any idea?

## REA book review question

### Re: REA book review question

Some people require that a subring contain the multiplicative identity.

### Re: REA book review question

Rings do have to be closed under multiplication

### Re: REA book review question

oh yes... thanks for the reply. I got it now.