Dim i As Integer, n As Integer, v As Variant, f As Variant

With CurrentDB.OpenRecordset( "select * from MyTable" )
    Do Until .EOF
        .MoveNext
        i =  0 
        v = Null
        For n =  1  to  10 
            Set f = .Fields( "F"  & CStr(n)).Value
            Select Case True
                Case IsNull(f)
                Case IsNull(v), f < v
                    v = f
                    i = n
            End Select
        Next
        .Edit
        !F11 = v
        !F12 = i
        .Update
    Loop
    .Close
End With