$2.$ Considering having a list of $10$ integers stored in a computer and named

x$1,$ x$2,$ x$3,...,$ x$9,$ x$10$

which you need to add up and store into a variable called result. Design a clear solution

to add up the numbers under each of the following condition

$($a$)$ In as few lines of code as you can.

$($b$)$ Assuming you can not perform more than one addition per line of code.

$($c$)$ A different approach using no more than one addition per line of code.