Total

Total[list] gives the total of the elements in list.

Total[list, n] totals all elements down to level n.

Examples

Sum a list:

Total[{1, 2, 3, 4, 5}]
(* 15 *)

Total of nested lists:

Total[{{1, 2}, {3, 4}}, 2]
(* 10 *)

Please visit the official Wolfram Language Reference for more details.