-0.9 - (-0.4) + 0.7 +(-0.7)
To solve this expression, we need to apply the minus sign to each term inside the parentheses.
-0.9 - (-0.4) + 0.7 + (-0.7)
-0.9 + 0.4 + 0.7 - 0.7
Now, we can combine the like terms:
(-0.9 + 0.4) + (0.7 - 0.7)
-0.5 + 0
The final result is -0.5.