123 - 100 - 3 = 20
456 + 44 + 300 = 800
123 + 123 + 123 + 123 = 492
789 + 789 + 789 + 567 = 2934
234 + 234 = 468
456 + 122 = 578
999 + 101 = 1100
456 + 123 = 579
143 + 123 = 266