54:18 91:13*4 60:15*9 70:14*8 (32-16)*4 (46-21)*3 (30-18)*7
54 /18 = 3 91 / 13 * 4 = 7 * 4 = 28 60 / 15 * 9 = 4 * 9 = 36 70 / 14 * 8 = 5 * 8 = 40 (32 - 16) * 4 = 16 * 4 = 64 (46 - 21) * 3 = 15 * 3 = 45 (30 - 18) * 7 = 12 * 7 = 84
54:18=3 91:13×4=28 60:15×9=36 70:4×8=40 (32-16)*4=64 (46-21)*3=75 (30-18)*7=84