Update table with random data

This is an MS Access 2010 related question.

Is it possible to update the (empty) field of an existing table with data that have no connection with those already in the other fields of the table?

Assuming I have a field called "Letters" with 3 records (A, B and C). How can I update the field "Numbers" with 1, 2 and 3? There is no connection at all between the values. I just want them to be in the same table. This should be done for large records and multiple fields.

Basically I am have to hold some reference date in the database and I would prefer to have them all in a single table.

The below retrieves the right numbers of records but they are all empty...

UPDATE tblDestination SET tblDestination.Numbers = [tblSource].[Numb];