"James Silverton" > wrote in message
...
> NOYDB wrote on Tue, 19 Oct 2010 02:26:28 -0400:
>
>> I find that I frequently want to adjust a recipe up or down in
>> quantity. I use an old slide rule to set up the original
>> proportion ( set the 1 over the adjusted quantity; 2, 3, .5,
>> whatever ) then read the new quantity directly under the
>> original quantity. Sometimes there's a problem in measuring
>> the new quantity exactly though.
>
>> Anyway I was wondering if anybody else does this or if I'm
>> just an old geek. I started using a sliderule studying
>> electronics in the '70's.
>
> I remember first enthusiastically coming across a slide rule at the age of
> 10. My father taught me some of the more simple usages and I still have a
> collection of the things both straight and circular. However, I usually
> still rely on mental arithmetic to adjust recipes even if I have several
> calculators lying around the house. One of them is even light powered.

That's what I do too. It's easy to do the math in my head. And sometimes I
will just write the adjusted numbers on the recipe in pencil.