Find the value of 4 (27 - 12 ∙ 2) ÷ 2.

You need to follow PEMDAS which stand for

Parentheses
Exponent 
Multiplication
Division
Adding
Subtraction

Or as I learned it (Please Excuse my Dear Aunt Sally)

So you need to do what it in the Parentheses first and in there do multiplication first

-12 times 2 -24

so take 27-24=3

3 times 4 because the 4 is out in front which is what we always do first after when we get to division and Multiplication so 3 times 4 is 12.

12/2= 6

So the Answer is 6