Alfred S Posamentier & Stephen Krulik 
PROBLEM-SOLVING STRATEGIES IN MATHEMATICS [EPUB ebook] 
From Common Approaches to Exemplary Strategies

This book introduces ten problem-solving strategies by first presenting the strategy and then applying it to problems in elementary mathematics. In doing so, first the common approach is shown, and then a more elegant strategy is provided. Elementary mathematics is used so that the reader can focus on the strategy and not be distracted by some more sophisticated mathematics.