This book features a collection of 54 decimal number puzzles designed to provide experiences in problem solving and mathematical reasoning for middle and high school students. Each puzzle consists of a sequence of 10 clues about an unknown decimal number. The clues, when revealed one at a time, lead students through deductive reasoning to the discovery of the unknown decimal number. Students need to know only basic definitions, concepts, and properties from numeration, number theory, and the arithmetic of fractions, decimals, and percents to solve the puzzles