2 5 x 3 7 7 5 x 3 7 July 8, 2019 16 32 64 128 2 3 x 4 5 2 3 x 2 5 7 x 7 7 Tính nhanh 2 3 x 4 5 2 3 x 2 5 7 x 7 7 5 x 7 = 35 −2 5 + (−3 7) + (− −7 5 )
