SEAMO 2020 — Paper E — Lớp 9–10 Câu hỏi 9

Tính $\frac{2020}{\sqrt1+\sqrt5}+\frac{2020}{\sqrt5+\sqrt9}+\frac{2020}{\sqrt9+\sqrt{13}}+\cdots+\frac{2020}{\sqrt{2021}+\sqrt{2025}}$.