BTVN 12/4

<p><a href="https://drive.google.com/drive/folders/12kB1zVbpjGWFLVQNbP-DWAiV7dSFjUG… là ví dụ 3,5/20 (dạng 1) + ví dụ 2,3/21 (dạng 2)</p>