1) $$5488 - 66 \cdot 83 = 5488 - 5478 = 10$$
2) $$(2823 - 2319) \cdot 23 = 504 \cdot 23 = 11592$$
3) $$45 \cdot (1238 - 148) = 45 \cdot 1090 = 49050$$
4) $$21 \cdot 106 - 106 = 2226 - 106 = 2120$$
Ответ: 1) 10; 2) 11592; 3) 49050; 4) 2120.