Perform the following operation. Write your solution. 2.8 x 9 + (48 : 6) = n 3. (72 + 15) x 4 - (625 +125) = n 을 1. 36 + (6 + 6) * 5 =n 4.5X6 + 6 +6 - 12 x 2 =n 5. 81 - 86 + 2 + (9 x 2) - 50 = n​