New York: Math 
Key Idea 1 Mathematical Reasoning
1A. Apply a variety of reasoning strategies.
Construct physical representations for complex problems.
Solve problems that illustrate the use of fractions and decimals.
State problem in own words.
Use a variety of problem-solving strategies.
Write and solve open sentences while working with word problems.
Use a simpler but related problem.
Use mathematical sentences to solve problems.
Use pictures, diagrams, or patterns.
Use proportional reasoning, ratios, and rates to solve problems.
Use trial and error (guess).