5 12 x 3 7 5 12 x 4 7 July 8, 2019 16 32 64 128 Tính nhanh 5 12 x 3 7 5 12 x 4 7 5 x 7 = 35 5 12 + 7/12 x 1 3/7 5 12 + 7/12 х 1 3/7 5 12 + 3 4
