How do I add numbers in certain cells of a spreadsheet

Select the sigma, select sum, in the formula bar I enter SUM(C8:C17:C26) - these are the cell locations of the spreadsheet. The results are wrong. Cell C8 has a figure of 486357.00. Cell C17 has a figure of 194195.82 and cell C26 has a figure of 612.52. The sum of these figure should be 671165.34. The above formula returns 875336.16.

The above formula returns 875336.16

The above Formula =SUM(C8:C17:C26) automatically changes to =SUM(C8:C26) and adds all values between C8 and C26 (Take care when using a range definition with more than one “:” separator, because you’ll end up in a max range defined by the cell addresses)

Use semicolons to address individual cells:

=SUM(C8;C17;C26)

(Commas may also work, depending on what you use for decimal separator.)

Cell addresses separated by colon specifies a range (from:to), which would sum the specified cells and all cells in between.