In this lesson, we‘ve learned the following key points:

1. We‘ve explained the specific use of SUM and SUMIF, SUMPRODUCT functions.

- They are all very common summation statistical functions in life. The SUM function can make a simple sum of the selected region, and the SUMIF function is an upgraded version of the SUM function, which can set a single condition and sum the data that matches the condition. Depending on how it is used, the SUMPRODUCT function can be used to obtain the product or the sum of products.

2. We‘ve explained the use of the AVERAGE function.

- Which can be averaged, and the  AVERAGEIF can set a single condition and average the data that matches the condition.

3. We've taken you guys to know the series of COUNT functions.

-Moreover, we've taken you guys to know the series of COUNT functions and helped to distinguish the different application scenarios among COUNT, COUNTA, COUNTBLANK, COUNTIF, and COUNTIFS functions.