The answer to, "if two is company and three is a crowd, what are five and four" is "nine." Although this riddle begins with two figures of speech, it ends with an addition problem.
There are many more examples of crafty math riddles. For instance, "What goes up but does not come back down?" The answer is, "a person's age."
Another classic question is, "What occurs once in every minute, twice in every moment and yet never in a thousand years?" The correct response is, "the letter m."
A tricky riddle asks, "If there are four apples and you take away three, how many do you have?" This is not a strict subtraction riddle, so the solution is not "one." Because the riddle states, "you take three away," the answer is "you have three."