This document discusses mathematical problem solving heuristics. It analyzes 13 heuristics identified in the Singapore mathematics syllabus and categorizes them into 4 groups: representation heuristics, simplification heuristics, pathway heuristics, and generic heuristics. Representation heuristics like "act it out" and "use a diagram" help represent problems in different forms. Simplification heuristics help remove unnecessary details to simplify problems. The document provides examples and analysis of how different heuristics can be applied to problem solving.