A DITLOID, sometimes known as an alpha-numeric, is a type of word puzzle, in which a phrase, quotation, date, or fact must be deduced from the numbers and abbreviated letters in the clue. Common words such as `the`, `in`, `a`, `an`, `of`, `to`, etc. are not normally abbreviated. It is usually written in the form of an equation such as 7=D in a W (Seven days in a week).
Here are some sheets containing examples. They are in pdf format and therefore can be printed out for use in your quizzes. I will add more over the coming months.
Find more quizzes at my main web-site www.kensquiz.co.uk