Question 444601
Let's start with something simple. Subtracting is the same as adding a negative number. 
And subtracting a negative number is the same as adding.
So,
4 - 1 = 4 + (-1)
4 - (-1) = 4 + 1 = 5
.
One thing that is useful to do is to put the operators "close" to what they are affecting.
4 - 1 = 4  -1
.
Or
4 - 3 [(2 - 8)-(-6 - 8)]
4 + (-3) * [2 + (-8) -(-6 + (-8))]
.
Start resolving this tangle with the innermost set of parentheses and work your way back out.
.
4 + (-3) * [2 + (-8) -(-6 -8))]
4 + (-3) * [2 + (-8) -(-14)]
4 + (-3) * [2 + (-8) +14)]
4 + (-3) * [2 + 6]
4 + (-3) * [8]
4 + (-3) * [8]
4 + (-24)
-20
.