First off, why would you want to do this? Will the values
need to *stay* synchronized? If so, just create reference
from on field to another. That being said, here's how to
do it. This would really depend on your table structure,
but the easiest way I can think of is this:
Function DoubleAdder()
Dim dbs as DAO.Database
Dim rst as DAO.Recordset
Dim rst2 as DAO.Recordset
Set dbs = CurrentDb()
Set rst = dbs.OpenRecordset("FirstTableNameHere")
Set rst2 = dbs.OpenRecordset("SecondTableNameHere")
rst.AddNew
rst.Fields("FieldNameInFirstTable") = <Control>
rst.Update
rst2.AddNew
rst2.Fields("FieldNameInSecondTable") = <Control>
rst2.Update
rst2.Close
rst2.Close
Set rst = Nothing
Set rst2 = Nothing
Set dbs = Nothing
End Function