21 乘法 80 等于多少？

21 × 79 = 1659 21 × 81 = 1701 21 × 78 = 1638 21 × 82 = 1722 21 × 83 = 1743 21 × 77 = 1617 21 × 84 = 1764 21 × 76 = 1596 20 × 80 = 1600 22 × 80 = 1760 19 × 80 = 1520 23 × 80 = 1840 24 × 80 = 1920 18 × 80 = 1440 25 × 80 = 2000 17 × 80 = 1360 20 × 84 = 1680 24 × 70 = 1680 28 × 60 = 1680 30 × 56 = 1680 35 × 48 = 1680 40 × 42 = 1680 52 × 4 = 208 12 × 62 = 744 85 × 78 = 6630 48 × 75 = 3600 23 × 12 = 276 21 × 46 = 966 68 × 13 = 884 12 × 89 = 1068