Solution 34618: Using the Sum( ) Function on a TI-84 Plus C Silver Edition.
How do I use the sum( ) function on a TI-84 Plus C Silver Edition?
The sum( function is used to find the sum of the elements in a list. The syntax is sum(list[,start, end]). The optional arguments and accompanying commas are enclosed in brackets. If included, it returns the sum of the elements of the list from start to end.Example: Find the sum of 1, 23, 453, 68.9, 59
• Press [2ND] [LIST].
• Press [→] to access the MATH menu and choose [5:sum(].

• Press [2nd] [{ ].
• Press [1] [,] [2] [3] [,] [4] [5] [3] [,] [6] [8] [.] [9] [,] [5] [9].
• Press [2nd] [ }] [ )].

• Press [ENTER] to get the answer of 604.9.

Please see the TI-84 Plus C Silver Edition guidebook for additional information.