Ответ:917 − 828 = 89.218 − 159 = 59.58 + 642 + 87 = 700 + 87 = 787.89 + 372 + 28 = (89 + 28) + 372 = 117 + 372 = 489.900 − 638 = 262.604 − 187 = 417.193 · 3 = 579.86 · 9 = 774.