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.

[245.466, 19.262, 199.878]
154.869

[82.439, -85.167, 100.665, -83.297]
3.66

[-42.16, -58.071, 148.805, 146.677, -61.711, -71.749, 233.782, -45.661, -87.345, 244.588]

40.716