I have made a little changes on CJ_London provided code.
SELECT tblCustomer.ID, tblCustomer.Name, tblCustomer.startno, tblCustomer.endno, tblCustomer.Noofleaves, Format([n]) AS Serial, [Name] & " " & Val([startno])+Val([Serial]) AS Datus
FROM t, tblCustomer
WHERE ((([t.n])<=[noofleaves]-1))...