91 加法 81 等于多少？

91 + 80 = 171 91 + 82 = 173 91 + 83 = 174 91 + 79 = 170 91 + 84 = 175 91 + 78 = 169 91 + 85 = 176 91 + 77 = 168 92 + 81 = 173 90 + 81 = 171 93 + 81 = 174 89 + 81 = 170 94 + 81 = 175 88 + 81 = 169 95 + 81 = 176 87 + 81 = 168 72 + 100 = 172 73 + 99 = 172 74 + 98 = 172 75 + 97 = 172 76 + 96 = 172 77 + 95 = 172 99 + 90 = 189 49 + 45 = 94 68 + 50 = 118 37 + 29 = 66 21 + 92 = 113 94 + 44 = 138 4 × 43 = 172 86 × 2 = 172