display all oppurtunities,

in the below code am getting error, can anyone tell me how to fix it?

display sum of amount of opportunities in a stage (stage name as parameter-> you can take any one stage name)
can anyone help on this?

can anyone solve the below questions?
create list on numbers
-> 1.find biggest number in that list
-> 2.find sum of odd and even numbers in the list (seperately)
-> 3.find any negative numbers in the list
-> 4. count number of negative numbers in the list and print the count
-> 5.reverse a list and store in a new list, print the new list

Can anyone solve this?

display sum of amount of opportunities in a stage (stage name as parameter-> you can take any one stage name)
can anyone help on this?