Calculator Puzzles, Tricks and Games

When pocket calculators first became available, it led to the development of an entirely new class of mathematical problems. Of the ten digits {0, ..., 9} represented in the digital display, seven look very similar to a letter when turned upside down. The new problem was to pose a riddle and present an arithmetic computation where the result, when turned upside down, would be the answer to the riddle. These problems are given the general name "calculator puzzles", hence the first category in the title. Calculator puzzles are extremely simple and can be solved by students in the upper grades of elementary school. The remaining puzzles are fairly standard mathematical puzzles and those generally considered "mental magic"; the level of difficulty is that of middle school. One example is: "In his last will and testament, Abe E. Sea left 25% of his wealth to charity. He left 50% of the remainder to his wife, and 12% of the remainder after that to each of his two sons. The balance of $11,400 went to his daughter. What was the total amount of his estate?" This is a book of problems where one category is quite simple and the others are a bit more complex but easily handled with the use of algebra. It is a nice collection of problems that can be used to sharpen and amuse people with an interest in puzzles based on basic mathematics.