I have a spreadsheet with headings Jan, Date Received, Feb, Date Received,
Mar, Date Received etc up to Dec.

An amount due in Jan is entered into the Jan column but date received could
be Jan, Feb or Mar. I need to add all amounts received in Jan which means I
need to look in all of the Date Received columns if the date falls between 1
and 31 Jan.

In the Feb column I need to look at amounts received in Feb and Jan and Mar
and total them. In conclusion I would total the amount due in Jan and show
the amount received in Jan. Any help would be appreciated.

Jan 2010 Date Received Feb 2010 Date Received

£100 02/01/2010 £500 28/01/2010
£7,587.35 06/03/2010 £7,144.68 10/02/2010
£5,847.02 05/02/2010 £4,090.86 02//03/2010