With the insertion point in the number, run the following code:

   Dim myrange As Range
   Set myrange = Selection.Words(1)
   Selection.Fields.Add Range:=myrange, Type:=wdFieldEmpty, _
       PreserveFormatting:=False
       myrange.Start = myrange.Start + 1
   myrange.InsertBefore "="
   myrange.InsertAfter "\*cardtext"
   ActiveWindow.View.ShowFieldCodes = Not ActiveWindow.View.ShowFieldCodes
   ActiveWindow.View.ShowFieldCodes = Not ActiveWindow.View.ShowFieldCodes
   Selection.Fields.Update