In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.

[-40.509, 201.39]
80.44

[9.392, -80.549]
-35.579

[143.464, 59.853, 6.334, 82.417, 70.465, 76.902, 115.095, 220.446, 234.369, 137.83]

114.718