4. 328-20 406-6 320:10-170:10 (750-50):100.1 1000-(200+300) 1000-(480-80)

Решение примеров: 1. $$328 - 20 = 308$$ $$406 - 6 = 400$$ 2. $$320 : 10 - 170 : 10 = 32 - 17 = 15$$ 3. $$(750 - 50) : 100 * 1 = 700 : 100 = 7$$ 4. $$1000 - (200 + 300) = 1000 - 500 = 500$$ 5. $$1000 - (480 - 80) = 1000 - 400 = 600$$