So I assume we're looking at the with " " as operation.
Generators of a group are elements that "generate" the group, that is, with these elements you can make any other element of the group.I don't know what generators are
Example: In the element "1" is allways a generator. Namely any element in G can be written as "1+1+1..+1" etc. Groups may have more then one generator. If a group can be generated by one element we call the group cyclic. Any additive group is cyclic.
Even though such a group is cyclic, there may exist more then one element in G that can generate the whole group.
Namely all with gcd are generators! Proper subgroups are generated by elements with gcd . (why?)
Thus proper subgroups are:
Now you try the other one: