1) 175 + 143 + 105 + 57 = (175 + 105) + (143 + 57) = 280 + 200 = 480
2) 123 + 74 + 157 + 26 + 20 = (123 + 157) + (74 + 26) + 20 = 280 + 100 + 20 = 400
3) 146 + 32 + 54 + 168 + 27 = (146 + 54) + (32 + 168) + 27 = 200 + 200 + 27 = 427
4) 154 + 65 + 46 + 135 + 18 = (154 + 46) + (65 + 135) + 18 = 200 + 200 +18 = 418