Slice the list

Given a list $L$ of numbers and its $length$, your task is to read these numbers into an array or a list. Assuming the index starts from 0, use the slice operations to do the following operations: - print list in reverse order - for every *third* number starting with index 0, add 3 to it and print them - for every *fifth* number starting with index 0, subtract 7 from it and print - add all the nu