12 x 5 3 x 4 x 6 12 July 8, 2019 16 32 64 128 7 5 x 12 3 x 24 5 x 4 6 x 12 x 2 Tính nhanh 12 x 5 3 x 4 x 6 12 12 5 x 1 4 12 x = 4 5 (12 5-x) 5=(3 6+x) 6 12 5 x 5