1, summation is the most commonly used summary method: in many cases, for the classified summary of numerical data, the most common requirement is to add the values under the same classification to get the sum. For example, when classifying and summarizing sales data, we are concerned about the total sales of each category, not the average sales or other indicators. Excel chooses summation as the default summary method to meet the common needs of most users.

2. Easy to understand and widely used: summation is a simple and intuitive summary method, which is easy to understand and use. There is no need for complicated calculation or additional settings, just simply add up the values in the same category. This conciseness makes summation the default summary method in Excel, which is suitable for all kinds of data analysis and report making scenarios.