\u0110\u1ec1 thi h\u1ecdc k\u00ec 1 l\u1edbp 12 m\u00f4n To\u00e1n n\u0103m 2019 S\u1edf GD&\u0110T B\u00ecnh D\u01b0\u01a1ng<\/a><\/blockquote><\/iframe>