Dear Excel Gurus,

I am seeking an INBUILT combination of functions (meaning NO programming thru' a macro or user-defined function!!) to find the sum of alternate values in a row.

For example, imagine I have numerical entries in a row, from A5 to U5, and in cell V5 I need to sum just alternate or 1-in-3 entries. That is, for the alternate case, just sum [A5,C5,E5,...], or in the case of 1-in-3, just sum [A5,D5,G5,...]. What formula in cell V5 will help me do this?

Obviously a simple: =SUM(A5:U5) won't do here. Is there something like: =SUM(A5:U5, 2) or =SUM(A5:U5, 3) which tells Excel to sum from A5:U5 BUT in steps of 2 or 3?

Please help... thanks in advance. Again, please note that I cannot afford a macro or some user-defined function to accomplish this.

Thanks.

- Om