Given
d = [[180.0], [173.8], [164.2], [156.5], [147.2], [138.2]]
and your specific question: How can I remove the brackets?
Using list comprehension :
new_d = [i[0] for i in d]
will give you this
[180.0, 173.8, 164.2, 156.5, 147.2, 138.2]
then you can access individual items with the appropriate index, e.g., new_d[0]
will give you 180.0
etc which you can then use for math.
If you are going to have a collection of data, you will have some sort of bracket or parenthesis.
Note, this solution is aimed specifically at your question/problem, it doesn't provide a generalized solution. I.e., it will work for your case.