0002132人目の素数さん垢版 | 大砲2023/09/18(月) 15:45:42.93ID:gGvopTwA (-1) * (-1) = (-1) * (-1) + 0 = (-1) * (-1) + (-1 + 1) = ((-1) * (-1) + (-1)) + 1 = ((-1) * (-1) + 1 * (-1)) + 1 = (-1 + 1) * (-1) + 1 = 0 * (-1) + 1 = 1