First, the brief summary of what I'm trying to do, then (for the
curious) a bit more explanation.

At the left side of my spreadsheet (column A), I want to have a
summation which reads:
=SUM(b2:hx2)
In other words, I want to sum all the values across a row (say, row 2)
of the spreadsheet. At the same time, I want to exclude the numeric
values in certain columns. But I do not want to have to put a clumsy
formula like:
=SUM(b2:hx2) - n2 - z2 - ck2, etc.
Instead, is there some way to flag or mark the indicated columns (n2,
z2, ck2, etc.), so that even though they remain numeric, they are not
included in the summation =SUM(b2:hx2)?

Motivation: The spreadsheet is being used to track hours for projects.
Each row is a project, each adjacent column is hours for a given day,
and I am summing across a row to track the total hours for each
project. But I also use the columns, at intervals, to track the weekly
totals. The goal, then, is to sum the total daily hours, but ignore
the columns with the weekly totals. So, the weekly total columns need
to remain numeric (so they can sum the hours for each week), but need
to be ignored by the master summary of total hours across the row?

Doable? (Easily!?)

Thanks in advance for all replies.
Steve