On Mon, 15 Apr 2013 13:06:03 GMT, Jethro_uk
wrote:

On Sat, 13 Apr 2013 15:59:26 +0100, Dave Plowman (News) wrote:

I was right that you never do the shopping. Pretty well all supermarkets
display a price per gram or whatever to allow you to compare actual
cost.

Not universally. Occasionally I have seen price per *Kg* for one item
against price per gram. Now to you and I it's a trivial issue. But given
the average standard of public mental arithmetic ...

Not as bad as price per Kg against price per litre.