Create Values From Ranges

I'll keep the analogy as basic as possible, but lets say we sell vouchers. The vouchers are individually numbered.

We sell the vouchers in batches, and are stored in the DB as one record per sale with a range of the vouchers sold (so they scan the first and last voucher number to get the range)

E.g.

Table1
SalesID Description From To
SalesID0001 Batch of paper 100001 100015
SalesID0002 More paper 100016 100150

The vouchers come back in individually however, so we might get voucher 100011 back and is stored in another table as an individual item.

I'm trying to write a report which shows which vouchers have not come back yet and I'm struggling since the data is stored in ranges not on an individual basis...?

My thinking is leading me to maybe create a temp table where I can convert those ranges into real numbers....which I'll be able to more easily compare - but how I might do that.

(Example output from above example

TempTable
SalesID Description Voucher
SalesID0001 Batch of paper 100001
SalesID0001 Batch of paper 100002
SalesID0001 Batch of paper 100003
SalesID0001 Batch of paper 100004
SalesID0001 Batch of paper 100005
etc, etc)