If I am correct the answer is 1.
You can do multiply 3 by 6/8 which will give you 2 1/4 or if in a decimal 2.25.
Then do 3 by -1/2 which will give you -1 1/2 and in decimal its -1.5.
You continue with the equation, 2.25 -1.5 = 0.75 + 0.25 = 1
Add them all together and you get 1...!
Hope this Helps :)