Creating a parent record where one record stores "Day One" for all records with 88 in the number field is likely your best bet here.
That requires defining a second table and linking the two tables.
The other approach is to write a script that a) finds all records with the same number and b) uses replace field contents to update them all with the newly selected value. That's most likely not good database design though there's a lot we don't know about your database and what you want to do here.
Using two tables:
Open Manage | Database | Tables and define a new table, I'll call it "Days".
Define two fields in it: Number, and DayLabel
Click the relationships tag and drag from Days::Number to the number field in your original table in order to relate them.
Click OK and create one record in Days for each value you've entered in the number field in your original table.
On your original layout, delete the drop down field and replace it with Days:: DayLabel. Format it with the same value list.
Now, when you select "Day one" for a record with 88 in the number field, you'll see Day One appear for all the other records with this name number.
There's a lot more to do here, but that should introduce the concept at least. You might want to read up on "Portals" in the filemaker help system as this is a very useful tool for working with groups of related records.
Thank you so much...I got that to work! Is there any way to make it work all on the same page? This way I have to change screens to choose from the drop-down menu. I would like to have the drop-down menu be available on the main page.
Just copy and paste the field from the new layout back to the original to put it in place of your original drop down field. You can put fields from other tables into your layout and edit data in them as long as you have a valid relationship linking your current record to a matching record in the other table.