Linked by Andy Roberts on Mon 6th Jun 2005 18:19 UTC
Anyone who has used Microsoft Word for a reasonable amount of time will recognise my very own Andy's Laws on Word:

Except you forgot the backslashes that open and close the math mode environment! I'll again for you,

$\sin (\alpha + \beta) = \sin\alpha\cos\beta + \cos\alpha\sin\beta$