That list is now approximately compared to the reference value. Your original solution now passes.

I see you are not. Do not take the 4 * ( .. ) into the parentheses.

I'll have a look at improving the tests, maybe do an approximate comparison over the list.

For now, you'll just have to follow the spec.

Order of calculations matters when doing floating point calculations. Are you following the exact spec as given in the description?

Great idea! It would be more fun to solve and cheat :) First thing I would do is to convert those to list and than back.