1 6 x 90 July 8, 2019 16 32 64 128 1 6 x 900 1 6 x 9000 1 6 10 x 90 1 2 x 6 90 90000 x 1 6 (1 5 x 1)+(1 x-6 1)=90 90 x 1 6 bằng bao nhiêu