=COUNTIF(Sheet1!$A$1:$A$4,"="&A1)+COUNTIF(Sheet2!$A$1:$A$4,"="&A1)+COUNTIF(Sheet3!$A$1:$A$4,"="&A1)
用countif 算次數
=SUMIF(Sheet1!$A$1:$A$5,"="&A1,Sheet1!$B$1:$B$5)+SUMIF(Sheet2!$A$1:$A$5,"="&A1,Sheet2!$B$1:$B$5)+SUMIF(Sheet3!$A$1:$A$5,"="&A1,Sheet3!$B$1:$B$5)
用sumif 算總合
sumif/countif= 平均值