SUM function: Returns the sum of numbers, logical values and text expressions of numbers in a cell range. The function MAX returns the largest value in a set of values. The function MIN returns the smallest value in a set of values. The function AVERAGE returns the average (arithmetic average) of the parameters. The RANK function returns the rank of the value of the specified field in the result set partition. The level of the specified field value is the level before the related line plus a specific level. You can check its introduction in excel and get to know it slowly, hehe. . .