A very simple example is:

What you need to is just distribute x into the parenthesis, so once x times the first term (a) and once x times the second term (b)
I hope you got
the idea
It would be 13.03 because the .008 with round the .02 up to .03.
A = 6, b = 3, c = 2
ab = 6 * 3 = 18
c + 4 = 2 + 4 = 6
a/b = 6/3 = 2
a - b = 6 - 3 = 3
2c = 2*2 = 4
b/3 = 3/3 = 1
a - 1 = 6 - 1 = 5
6 + c = 6 + 2 = 8