Write a Python program to get the cumulative sum of the elements of a given list.

Example: If the list is [1, 3, 5, 7, 9], then the list of the cumulative sum is [1, 4, 9, 16, 25].

Write a Python program to count the number 3 in a given list.

Write a Python program to get the largest number from a list.

Write a Python program to get the smallest number from a list.