Find a cyclic subgroup and a noncycle subgroup of order 4 in

Find a cyclic subgroup and a non-cycle subgroup of order 4 in U(40). How many cyclic subgroups does U(40) have?

<3> is a cyclic group of order 4 since <3> ={1,3,9,27} and it is cyclic group of order 4 as 3^0=1,3^3=9,3^3=27,3^4=1mod40

further 9 and 39 both are of order 2 since 9^0=1,9^1=9,9^2=1mod40

and 39^0=1,39^2=1mod40, <9,39> is asubgroup of U(40) of order 4 and is non cyclic.