In a previous article, "kage" said:
double the C
subtract 10%
add 32

Exact

Add 40. Multiply by 9/5 or 5/9 depending on whether you're going F-C or
C-F. Subtract 40. Works both ways, exactly.


--
Paul Tomblin http://xcski.com/blogs/pt/
Mentally update my CV, paying special attention to the bits
about how to say "Was Fired For Being A Prat" in a positive light.
-- Eric the Read's bad day