Ответ:6 + 7 − 9 = 13 − 9 = 4.10 + 3 − 4 = 13 − 4 = 9.18 − 10 + 5 = 8 + 5 = 13.15 − (3 + 5) = 15 − 8 = 7.8 + (12 − 5) = 8 + 7 = 15.9 + (13 − 7) = 9 + 6 = 15.