28,3+(-1,8+6)-(18,2-11,7)

To solve this expression, we need to follow the order of operations:

1. Start by solving inside the parentheses first: -1.8 + 6 = 4.2 (addition) 18.2 - 11.7 = 6.5 (subtraction)

2. Substitute the results back into the original expression: 28.3 + 4.2 - 6.5

3. Lastly, perform the addition and subtraction: 28.3 + 4.2 = 32.5 32.5 - 6.5 = 26

Therefore, the final result of the expression 28.3 + (-1.8 + 6) - (18.2 - 11.7) is 26.