Originally Posted by

**tonio** For (a) I'd rather say there are infinite E-eq. classes since there are infinite primes and we can form a

natural number with any arbitrary number of different primes

For (b) the answer is not since the E-eq. class of {1} has ony two elements (which natural is the other one?)

For (c) check that for example [101] = [103] (why?), [102]=[105] (why?), etc.

For (d) check how many different primes divide 120, and then form the 6 lowest possible numbers with those divisors

Tonio