if a)=0.65 and b)=1.28 and c)=-5/2,evaluate -a-(-b)+c
No trick here. Just plug in the numbers, start from the innermost parens, and plug away.
-a - (-b) + c
-0.65 - (-1.28) + (-2.5)
-0.65 + 1.28 - 2.5
-1.87
-a - (-b) + c
-0.65 - (-1.28) + (-2.5)
-0.65 + 1.28 - 2.5
-1.87