4. Модуль числа - 6. Додавання цілих чисел » 207

а) 28 + (–55) + 32 + (–28) + 55 = 28 + (–28) + 55 + (–55) + 32 = 32; б) –76 + 237 + 176 + (–37) = –76 + 176 + 237 + (–37) = 100 + 200 = 300; в) (68 + (–72)) + (–68) = 68 + (–68) + (–72) = –72; г) (–17 + (–12)) + 12 = (–12 + 12) + (–17) = –17.