Originally Posted by
rudestuff
I thought a mnemonic was supposed to mean something - like "Cadburys Dairy Milk Very Tasty"
That's correct; or the other way round True Virgins Make Dull Company. I learned both of these over 50 years ago. Another good one is CADET: draw an arrow above the word from the C to the T, then underline the three letters in the middle. You then get Compass to True Add East. This + and - for deviation seems unique to aircraft navigation, I never encountered this as a navigator at sea. The question gives both descriptions for deviation i.e. minus and west.