I have a Microsoft Excel Users Manuel that says the following on calculating
part of a formula. (This is apparently Version 4 so the info is out of date.)

1. Select the cell containing the formula or type the formula in the formula
bar.
2. In the formula bar, select the portion of the formula you want to
calculate.
3. Press F9
4. Click the enter box or press ENTER

My cell has this formula:
=SUM(B5,B7,B9,B11,B13,B15,B17,B19,B21,B23,B25,B27)

Right now I only want it to calculate =SUM(B5,B7,B9,B11) but I need to keep
the rest of the formula. i can get it to calculate correctly but it won't put
it in a useable format for the cell and I get an error. So basically it gets
to step 3 but won't let me enter the value. Do I need to make any other
setting changes?