Recreational mathematics consists of mathematical games and puzzles that are often designed for a popular (i.e., not mathematically astute) audience and are typically based on ideas from discrete mathematics, especially elementary concepts of probability, combinatorics and number theory, since these areas focus on familiar objects and ideas, but involve many subtleties. Many companies ask puzzle-type questions during interviews to test the ability of the interviewee. Strong math and analytical skills required to solve these puzzles.