You need to create a function and then return the output of the addition. A function which takes two arguments.
def addition(number1, number2):
return number1 + number2
number1 and number2 are the 2 arguments. Since you already have 2 numbers in your list you can pass them like this.
print(addition(*randomlist))
The * unpacks the items in your list and passes them as seperate variables.
I would suggest doing some reading on python functions
solved How to sum random two numbers?