If you’re preparing for the SOA Exam C and want to master loss reserving, getting comfortable with actuarial loss development triangles in Excel is a must. These triangles are fundamental tools for analyzing how insurance claims evolve over time, helping you estimate reserves and understand the behavior of losses from accident years through development periods. Let me walk you through a clear, step-by-step tutorial on creating and interpreting these triangles in Excel, with practical tips to boost your confidence and efficiency.