(258 + 693): 3 (185+590): 5 (455 + 189): 7 (378 +534): 6

To solve these expressions, we can simply divide the sum by the given number.

1. (258 + 693): 3 Sum = 258 + 693 = 951 951 ÷ 3 = 317

2. (185 + 590): 5 Sum = 185 + 590 = 775 775 ÷ 5 = 155

3. (455 + 189): 7 Sum = 455 + 189 = 644 644 ÷ 7 = 92

4. (378 + 534): 6 Sum = 378 + 534 = 912 912 ÷ 6 = 152

So, the answers are:

1. 317
2. 155
3. 92
4. 152