Every
subgroup of a cyclic group is cyclic.
Moreover, if 
, then the order of any subgroup of 
is a divisor of n. In addition, for each positive divisor k of n,
the group has exactly one subgroup of order k, namely 
.
Every
subgroup of a cyclic group is cyclic.
Moreover, if , then the order of any subgroup of is a divisor of n. In addition, for each positive divisor k of n,
the group has exactly one subgroup of order k, namely .