简便运算（乘法分配律）450 道 28 × 29 + 42 × 29 = 34 × 38 + 46 × 38 = 7 × 70 + 7 × 20 = 71 × 68 + 71 × 22 = 72 × 11 + 72 × 49 = 27 × 24 + 27 × 46 = 55 × 43 + 55 × 17 = 76 × 3 + 76 × 77 = 45 × 68 + 5 × 68 = 61 × 23 + 61 × 37 = 30 × 35 + 30 × 35 = 4 × 84 + 66 × 84 = 46 × 49 + 46 × 1 = 52 × 96 + 8 × 96 = 34 × 19 + 36 × 19 = 46 × 39 + 44 × 39 = 30 × 65 + 30 × 5 = 83 × 36 + 83 × 4 = 27 × 34 + 23 × 34 = 27 × 75 + 27 × 15 = 5 × 30 + 5 × 20 = 34 × 84 + 6 × 84 = 62 × 6 + 62 × 24 = 26 × 5 + 64 × 5 = 4 × 86 + 16 × 86 = 36 × 52 + 4 × 52 = 3 × 87 + 67 × 87 = 76 × 39 + 76 × 11 = 55 × 99 + 15 × 99 = 61 × 29 + 29 × 29 = 54 × 70 + 6 × 70 = 19 × 32 + 19 × 48 = 53 × 26 + 27 × 26 = 25 × 28 + 55 × 28 = 3 × 53 + 57 × 53 = 67 × 15 + 67 × 55 = 64 × 24 + 64 × 6 = 74 × 47 + 74 × 33 = 84 × 78 + 84 × 2 = 9 × 68 + 61 × 68 = 54 × 9 + 54 × 21 = 48 × 27 + 48 × 3 = 75 × 44 + 5 × 44 = 28 × 2 + 32 × 2 = 5 × 5 + 5 × 25 = 62 × 48 + 62 × 2 = 37 × 35 + 23 × 35 = 48 × 63 + 48 × 17 = 48 × 88 + 22 × 88 = 12 × 91 + 78 × 91 = 83 × 35 + 83 × 5 = 81 × 35 + 81 × 15 = 20 × 44 + 60 × 44 = 63 × 17 + 63 × 13 = 25 × 68 + 45 × 68 = 22 × 86 + 58 × 86 = 26 × 90 + 34 × 90 = 36 × 8 + 54 × 8 = 66 × 92 + 14 × 92 = 3 × 30 + 3 × 20 = 7 × 52 + 7 × 38 = 7 × 82 + 43 × 82 = 75 × 64 + 75 × 26 = 24 × 36 + 24 × 24 = 26 × 2 + 26 × 68 = 37 × 31 + 37 × 59 = 98 × 25 + 98 × 35 ...
