Definition Let ∑an be a Series ∑an conditionally converges ⟺∑∣an∣ diverges, but ∑an converges Or, in other words, our series Converges but does not Absolute Converge Properties Rearrangement Property If ∑an conditionally converges Then, ∀r∈R there exists an arrangement of ∑an s.t ∑an=r